diff --git a/src/dom/document.zig b/src/dom/document.zig
index 8bb4577d..846c2f32 100644
--- a/src/dom/document.zig
+++ b/src/dom/document.zig
@@ -34,9 +34,10 @@ pub const Document = struct {
         return DOMImplementation{};
     }
 
-    pub fn get_documentElement(self: *parser.Document) !ElementUnion {
+    pub fn get_documentElement(self: *parser.Document) !?ElementUnion {
         const e = try parser.documentGetDocumentElement(self);
-        return try Element.toInterface(e);
+        if (e == null) return null;
+        return try Element.toInterface(e.?);
     }
 
     pub fn get_documentURI(self: *parser.Document) ![]const u8 {
@@ -105,12 +106,12 @@ pub const Document = struct {
         alloc: std.mem.Allocator,
         tag_name: []const u8,
     ) !collection.HTMLCollection {
-        const root = try parser.documentGetDocumentElement(self);
-        return try collection.HTMLCollectionByTagName(
-            alloc,
-            parser.elementToNode(root),
-            tag_name,
-        );
+        var elt: ?*parser.Node = null;
+        if (try parser.documentGetDocumentElement(self)) |root| {
+            elt = parser.elementToNode(root);
+        }
+
+        return try collection.HTMLCollectionByTagName(alloc, elt, tag_name, true);
     }
 
     pub fn _getElementsByClassName(
@@ -118,12 +119,12 @@ pub const Document = struct {
         alloc: std.mem.Allocator,
         classNames: []const u8,
     ) !collection.HTMLCollection {
-        const root = try parser.documentGetDocumentElement(self);
-        return try collection.HTMLCollectionByClassName(
-            alloc,
-            parser.elementToNode(root),
-            classNames,
-        );
+        var elt: ?*parser.Node = null;
+        if (try parser.documentGetDocumentElement(self)) |root| {
+            elt = parser.elementToNode(root);
+        }
+
+        return try collection.HTMLCollectionByClassName(alloc, elt, classNames, true);
     }
 
     pub fn _createDocumentFragment(self: *parser.Document) !*parser.DocumentFragment {
@@ -164,6 +165,31 @@ pub const Document = struct {
         return try parser.documentCreateAttributeNS(self, ns, qname);
     }
 
+    // ParentNode
+    // https://dom.spec.whatwg.org/#parentnode
+    pub fn get_children(self: *parser.Document) !collection.HTMLCollection {
+        var elt: ?*parser.Node = null;
+        if (try parser.documentGetDocumentElement(self)) |root| {
+            elt = parser.elementToNode(root);
+        }
+        return try collection.HTMLCollectionChildren(elt, true);
+    }
+
+    pub fn get_firstElementChild(self: *parser.Document) !?ElementUnion {
+        const elt = try parser.documentGetDocumentElement(self) orelse return null;
+        return try Element.toInterface(elt);
+    }
+
+    pub fn get_lastElementChild(self: *parser.Document) !?ElementUnion {
+        const elt = try parser.documentGetDocumentElement(self) orelse return null;
+        return try Element.toInterface(elt);
+    }
+
+    pub fn get_childElementCount(self: *parser.Document) !u32 {
+        _ = try parser.documentGetDocumentElement(self) orelse return 0;
+        return 1;
+    }
+
     pub fn deinit(_: *parser.Document, _: std.mem.Allocator) void {}
 };
 
@@ -179,6 +205,12 @@ pub fn testExecFn(
         .{ .src = "document.__proto__.__proto__.constructor.name", .ex = "Document" },
         .{ .src = "document.__proto__.__proto__.__proto__.constructor.name", .ex = "Node" },
         .{ .src = "document.__proto__.__proto__.__proto__.__proto__.constructor.name", .ex = "EventTarget" },
+
+        .{ .src = "let newdoc = new Document()", .ex = "undefined" },
+        .{ .src = "newdoc.documentElement", .ex = "null" },
+        .{ .src = "newdoc.children.length", .ex = "0" },
+        .{ .src = "newdoc.getElementsByTagName('*').length", .ex = "0" },
+        .{ .src = "newdoc.getElementsByTagName('*').item(0)", .ex = "null" },
     };
     try checkCases(js_env, &constructor);
 
@@ -306,6 +338,22 @@ pub fn testExecFn(
     };
     try checkCases(js_env, &createAttr);
 
+    var parentNode = [_]Case{
+        .{ .src = "document.children.length", .ex = "1" },
+        .{ .src = "document.children.item(0).nodeName", .ex = "HTML" },
+        .{ .src = "document.firstElementChild.nodeName", .ex = "HTML" },
+        .{ .src = "document.lastElementChild.nodeName", .ex = "HTML" },
+        .{ .src = "document.childElementCount", .ex = "1" },
+
+        .{ .src = "let nd = new Document()", .ex = "undefined" },
+        .{ .src = "nd.children.length", .ex = "0" },
+        .{ .src = "nd.children.item(0)", .ex = "null" },
+        .{ .src = "nd.firstElementChild", .ex = "null" },
+        .{ .src = "nd.lastElementChild", .ex = "null" },
+        .{ .src = "nd.childElementCount", .ex = "0" },
+    };
+    try checkCases(js_env, &parentNode);
+
     const tags = comptime parser.Tag.all();
     comptime var createElements: [(tags.len) * 2]Case = undefined;
     inline for (tags, 0..) |tag, i| {
diff --git a/src/dom/element.zig b/src/dom/element.zig
index aa8bc2f5..1a506681 100644
--- a/src/dom/element.zig
+++ b/src/dom/element.zig
@@ -6,6 +6,8 @@ const jsruntime = @import("jsruntime");
 const Case = jsruntime.test_utils.Case;
 const checkCases = jsruntime.test_utils.checkCases;
 
+const collection = @import("html_collection.zig");
+
 const Node = @import("node.zig").Node;
 const HTMLElem = @import("../html/elements.zig");
 pub const Union = @import("../html/elements.zig").Union;
@@ -122,6 +124,60 @@ pub const Element = struct {
         // Return true.
         return true;
     }
+
+    pub fn _getElementsByTagName(
+        self: *parser.Element,
+        alloc: std.mem.Allocator,
+        tag_name: []const u8,
+    ) !collection.HTMLCollection {
+        return try collection.HTMLCollectionByTagName(
+            alloc,
+            parser.elementToNode(self),
+            tag_name,
+            false,
+        );
+    }
+
+    pub fn _getElementsByClassName(
+        self: *parser.Element,
+        alloc: std.mem.Allocator,
+        classNames: []const u8,
+    ) !collection.HTMLCollection {
+        return try collection.HTMLCollectionByClassName(
+            alloc,
+            parser.elementToNode(self),
+            classNames,
+            false,
+        );
+    }
+
+    // ParentNode
+    // https://dom.spec.whatwg.org/#parentnode
+    pub fn get_children(self: *parser.Element) !collection.HTMLCollection {
+        return try collection.HTMLCollectionChildren(parser.elementToNode(self), false);
+    }
+
+    pub fn get_firstElementChild(self: *parser.Element) !?Union {
+        var children = try get_children(self);
+        return try children._item(0);
+    }
+
+    pub fn get_lastElementChild(self: *parser.Element) !?Union {
+        // TODO we could check the last child node first, if it's an element,
+        // we can return it directly instead of looping twice over the
+        // children.
+        var children = try get_children(self);
+        const ln = try children.get_length();
+        if (ln == 0) return null;
+        return try children._item(ln - 1);
+    }
+
+    pub fn get_childElementCount(self: *parser.Element) !u32 {
+        var children = try get_children(self);
+        return try children.get_length();
+    }
+
+    pub fn deinit(_: *parser.Element, _: std.mem.Allocator) void {}
 };
 
 // Tests
@@ -192,4 +248,13 @@ pub fn testExecFn(
         .{ .src = "b.hasAttribute('foo')", .ex = "false" },
     };
     try checkCases(js_env, &toggleAttr);
+
+    var parentNode = [_]Case{
+        .{ .src = "let c = document.getElementById('content')", .ex = "undefined" },
+        .{ .src = "c.children.length", .ex = "3" },
+        .{ .src = "c.firstElementChild.nodeName", .ex = "A" },
+        .{ .src = "c.lastElementChild.nodeName", .ex = "P" },
+        .{ .src = "c.childElementCount", .ex = "3" },
+    };
+    try checkCases(js_env, &parentNode);
 }
diff --git a/src/dom/html_collection.zig b/src/dom/html_collection.zig
index ec32d2a2..da4bf2f6 100644
--- a/src/dom/html_collection.zig
+++ b/src/dom/html_collection.zig
@@ -14,16 +14,21 @@ const Union = @import("element.zig").Union;
 const Matcher = union(enum) {
     matchByTagName: MatchByTagName,
     matchByClassName: MatchByClassName,
+    matchTrue: struct {},
 
     pub fn match(self: Matcher, node: *parser.Node) !bool {
         switch (self) {
-            inline else => |case| return case.match(node),
+            inline .matchTrue => return true,
+            inline .matchByTagName => |case| return case.match(node),
+            inline .matchByClassName => |case| return case.match(node),
         }
     }
 
     pub fn deinit(self: Matcher, alloc: std.mem.Allocator) void {
         switch (self) {
-            inline else => |case| return case.deinit(alloc),
+            inline .matchTrue => return,
+            inline .matchByTagName => |case| return case.deinit(alloc),
+            inline .matchByClassName => |case| return case.deinit(alloc),
         }
     }
 };
@@ -54,14 +59,17 @@ pub const MatchByTagName = struct {
 
 pub fn HTMLCollectionByTagName(
     alloc: std.mem.Allocator,
-    root: *parser.Node,
+    root: ?*parser.Node,
     tag_name: []const u8,
+    include_root: bool,
 ) !HTMLCollection {
     return HTMLCollection{
         .root = root,
+        .walker = Walker{ .walkerDepthFirst = .{} },
         .matcher = Matcher{
             .matchByTagName = try MatchByTagName.init(alloc, tag_name),
         },
+        .include_root = include_root,
     };
 }
 
@@ -95,17 +103,108 @@ pub const MatchByClassName = struct {
 
 pub fn HTMLCollectionByClassName(
     alloc: std.mem.Allocator,
-    root: *parser.Node,
+    root: ?*parser.Node,
     classNames: []const u8,
+    include_root: bool,
 ) !HTMLCollection {
     return HTMLCollection{
         .root = root,
+        .walker = Walker{ .walkerDepthFirst = .{} },
         .matcher = Matcher{
             .matchByClassName = try MatchByClassName.init(alloc, classNames),
         },
+        .include_root = include_root,
     };
 }
 
+pub fn HTMLCollectionChildren(
+    root: ?*parser.Node,
+    include_root: bool,
+) !HTMLCollection {
+    return HTMLCollection{
+        .root = root,
+        .walker = Walker{ .walkerChildren = .{} },
+        .matcher = Matcher{ .matchTrue = .{} },
+        .include_root = include_root,
+    };
+}
+
+const Walker = union(enum) {
+    walkerDepthFirst: WalkerDepthFirst,
+    walkerChildren: WalkerChildren,
+
+    pub fn get_next(self: Walker, root: *parser.Node, cur: ?*parser.Node) !?*parser.Node {
+        switch (self) {
+            inline else => |case| return case.get_next(root, cur),
+        }
+    }
+};
+
+// WalkerDepthFirst iterates over the DOM tree to return the next following
+// node or null at the end.
+//
+// This implementation is a zig version of Netsurf code.
+// http://source.netsurf-browser.org/libdom.git/tree/src/html/html_collection.c#n177
+//
+// The iteration is a depth first as required by the specification.
+// https://dom.spec.whatwg.org/#htmlcollection
+// https://dom.spec.whatwg.org/#concept-tree-order
+pub const WalkerDepthFirst = struct {
+    pub fn get_next(_: WalkerDepthFirst, root: *parser.Node, cur: ?*parser.Node) !?*parser.Node {
+        var n = cur orelse root;
+
+        // TODO deinit next
+        if (try parser.nodeFirstChild(n)) |next| {
+            return next;
+        }
+
+        // TODO deinit next
+        if (try parser.nodeNextSibling(n)) |next| {
+            return next;
+        }
+
+        // TODO deinit parent
+        // Back to the parent of cur.
+        // If cur has no parent, then the iteration is over.
+        var parent = try parser.nodeParentNode(n) orelse return null;
+
+        // TODO deinit lastchild
+        var lastchild = try parser.nodeLastChild(parent);
+        while (n != root and n == lastchild) {
+            n = parent;
+
+            // TODO deinit parent
+            // Back to the prev's parent.
+            // If prev has no parent, then the loop must stop.
+            parent = try parser.nodeParentNode(n) orelse break;
+
+            // TODO deinit lastchild
+            lastchild = try parser.nodeLastChild(parent);
+        }
+
+        if (n == root) {
+            return null;
+        }
+
+        return try parser.nodeNextSibling(n);
+    }
+};
+
+// WalkerChildren iterates over the root's children only.
+pub const WalkerChildren = struct {
+    pub fn get_next(_: WalkerChildren, root: *parser.Node, cur: ?*parser.Node) !?*parser.Node {
+        // On walk start, we return the first root's child.
+        if (cur == null) return try parser.nodeFirstChild(root);
+
+        // If cur is root, then return null.
+        // This is a special case, if the root is included in the walk, we
+        // don't want to go further to find children.
+        if (root == cur.?) return null;
+
+        return try parser.nodeNextSibling(cur.?);
+    }
+};
+
 // WEB IDL https://dom.spec.whatwg.org/#htmlcollection
 // HTMLCollection is re implemented in zig here because libdom
 // dom_html_collection expects a comparison function callback as arguement.
@@ -114,96 +213,68 @@ pub const HTMLCollection = struct {
     pub const mem_guarantied = true;
 
     matcher: Matcher,
+    walker: Walker,
 
-    root: *parser.Node,
+    root: ?*parser.Node,
+
+    // By default the HTMLCollection walk on the root's descendant only.
+    // But on somes cases, like for dom document, we want to walk over the root
+    // itself.
+    include_root: bool = false,
 
     // save a state for the collection to improve the _item speed.
     cur_idx: ?u32 = undefined,
     cur_node: ?*parser.Node = undefined,
 
-    // get_next iterates over the DOM tree to return the next following node or
-    // null at the end.
-    //
-    // This implementation is a zig version of Netsurf code.
-    // http://source.netsurf-browser.org/libdom.git/tree/src/html/html_collection.c#n177
-    //
-    // The iteration is a depth first as required by the specification.
-    // https://dom.spec.whatwg.org/#htmlcollection
-    // https://dom.spec.whatwg.org/#concept-tree-order
-    fn get_next(root: *parser.Node, cur: *parser.Node) !?*parser.Node {
-        // TODO deinit next
-        if (try parser.nodeFirstChild(cur)) |next| {
-            return next;
+    // start returns the first node to walk on.
+    fn start(self: HTMLCollection) !?*parser.Node {
+        if (self.root == null) return null;
+
+        if (self.include_root) {
+            return self.root.?;
         }
 
-        // TODO deinit next
-        if (try parser.nodeNextSibling(cur)) |next| {
-            return next;
-        }
-
-        // TODO deinit parent
-        // Back to the parent of cur.
-        // If cur has no parent, then the iteration is over.
-        var parent = try parser.nodeParentNode(cur) orelse return null;
-
-        // TODO deinit lastchild
-        var lastchild = try parser.nodeLastChild(parent);
-        var prev = cur;
-        while (prev != root and prev == lastchild) {
-            prev = parent;
-
-            // TODO deinit parent
-            // Back to the prev's parent.
-            // If prev has no parent, then the loop must stop.
-            parent = try parser.nodeParentNode(prev) orelse break;
-
-            // TODO deinit lastchild
-            lastchild = try parser.nodeLastChild(parent);
-        }
-
-        if (prev == root) {
-            return null;
-        }
-
-        return try parser.nodeNextSibling(prev);
+        return try self.walker.get_next(self.root.?, null);
     }
 
     /// get_length computes the collection's length dynamically according to
     /// the current root structure.
     // TODO: nodes retrieved must be de-referenced.
     pub fn get_length(self: *HTMLCollection) !u32 {
+        if (self.root == null) return 0;
+
         var len: u32 = 0;
-        var node: *parser.Node = self.root;
-        var ntype: parser.NodeType = undefined;
+        var node = try self.start() orelse return 0;
 
         while (true) {
-            ntype = try parser.nodeType(node);
-            if (ntype == .element) {
+            if (try parser.nodeType(node) == .element) {
                 if (try self.matcher.match(node)) {
                     len += 1;
                 }
             }
 
-            node = try get_next(self.root, node) orelse break;
+            node = try self.walker.get_next(self.root.?, node) orelse break;
         }
 
         return len;
     }
 
     pub fn _item(self: *HTMLCollection, index: u32) !?Union {
+        if (self.root == null) return null;
+
         var i: u32 = 0;
-        var node: *parser.Node = self.root;
-        var ntype: parser.NodeType = undefined;
+        var node: *parser.Node = undefined;
 
         // Use the current state to improve speed if possible.
         if (self.cur_idx != null and index >= self.cur_idx.?) {
             i = self.cur_idx.?;
             node = self.cur_node.?;
+        } else {
+            node = try self.start() orelse return null;
         }
 
         while (true) {
-            ntype = try parser.nodeType(node);
-            if (ntype == .element) {
+            if (try parser.nodeType(node) == .element) {
                 if (try self.matcher.match(node)) {
                     // check if we found the searched element.
                     if (i == index) {
@@ -219,23 +290,20 @@ pub const HTMLCollection = struct {
                 }
             }
 
-            node = try get_next(self.root, node) orelse break;
+            node = try self.walker.get_next(self.root.?, node) orelse break;
         }
 
         return null;
     }
 
     pub fn _namedItem(self: *HTMLCollection, name: []const u8) !?Union {
-        if (name.len == 0) {
-            return null;
-        }
+        if (self.root == null) return null;
+        if (name.len == 0) return null;
 
-        var node: *parser.Node = self.root;
-        var ntype: parser.NodeType = undefined;
+        var node = try self.start() orelse return null;
 
         while (true) {
-            ntype = try parser.nodeType(node);
-            if (ntype == .element) {
+            if (try parser.nodeType(node) == .element) {
                 if (try self.matcher.match(node)) {
                     const elem = @as(*parser.Element, @ptrCast(node));
 
@@ -253,7 +321,7 @@ pub const HTMLCollection = struct {
                 }
             }
 
-            node = try get_next(self.root, node) orelse break;
+            node = try self.walker.get_next(self.root.?, node) orelse break;
         }
 
         return null;
@@ -290,6 +358,13 @@ pub fn testExecFn(
         .{ .src = "getElementsByTagNameAll.item(7).localName", .ex = "p" },
         .{ .src = "getElementsByTagNameAll.namedItem('para-empty-child').localName", .ex = "span" },
 
+        .{ .src = "document.getElementById('content').getElementsByTagName('*').length", .ex = "4" },
+        .{ .src = "document.getElementById('content').getElementsByTagName('p').length", .ex = "2" },
+        .{ .src = "document.getElementById('content').getElementsByTagName('div').length", .ex = "0" },
+
+        .{ .src = "document.children.length", .ex = "1" },
+        .{ .src = "document.getElementById('content').children.length", .ex = "3" },
+
         // check liveness
         .{ .src = "let content = document.getElementById('content')", .ex = "undefined" },
         .{ .src = "let pe = document.getElementById('para-empty')", .ex = "undefined" },
diff --git a/src/netsurf.zig b/src/netsurf.zig
index 3f8336ff..2455b35a 100644
--- a/src/netsurf.zig
+++ b/src/netsurf.zig
@@ -1150,10 +1150,11 @@ pub inline fn documentGetElementsByTagName(doc: *Document, tagname: []const u8)
 }
 
 // documentGetDocumentElement returns the root document element.
-pub inline fn documentGetDocumentElement(doc: *Document) !*Element {
+pub inline fn documentGetDocumentElement(doc: *Document) !?*Element {
     var elem: ?*Element = undefined;
     const err = documentVtable(doc).dom_document_get_document_element.?(doc, &elem);
     try DOMErr(err);
+    if (elem == null) return null;
     return elem.?;
 }
 
diff --git a/tests/wpt/dom/Document-getElementsByClassName.html b/tests/wpt/dom/nodes/Document-getElementsByClassName.html
similarity index 100%
rename from tests/wpt/dom/Document-getElementsByClassName.html
rename to tests/wpt/dom/nodes/Document-getElementsByClassName.html
diff --git a/tests/wpt/dom/nodes/Element-childElement-null-svg.svg b/tests/wpt/dom/nodes/Element-childElement-null-svg.svg
new file mode 100644
index 00000000..38848287
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-childElement-null-svg.svg
@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg"
+     xmlns:h="http://www.w3.org/1999/xhtml"
+     version="1.1"
+     width="100%" height="100%" viewBox="0 0 400 400">
+<title>Null test</title>
+<h:script src="/resources/testharness.js"/>
+<h:script src="/resources/testharnessreport.js"/>
+
+<text x="200" y="40" font-size="25" fill="black" text-anchor="middle">Test of firstElementChild and lastChildElement returning null</text>
+<text id="parentEl" x="200" y="70" font-size="20" fill="black" text-anchor="middle" font-weight="bold">Test</text>
+
+<h:script><![CDATA[
+test(function() {
+  var parentEl = document.getElementById("parentEl")
+  assert_equals(parentEl.firstElementChild, null)
+  assert_equals(parentEl.lastElementChild, null)
+})
+]]></h:script>
+</svg>
diff --git a/tests/wpt/dom/nodes/Element-childElement-null-xhtml.xhtml b/tests/wpt/dom/nodes/Element-childElement-null-xhtml.xhtml
new file mode 100644
index 00000000..daedab6d
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-childElement-null-xhtml.xhtml
@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<html xmlns="http://www.w3.org/1999/xhtml">
+<head>
+<title>Null Test</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+</head>
+<body>
+<h1>Test of firstElementChild and lastChildElement returning null</h1>
+<div id="log"></div>
+<p id="parentEl" style="font-weight:bold;">Test.</p>
+<script><![CDATA[
+test(function() {
+  var parentEl = document.getElementById("parentEl")
+  assert_equals(parentEl.firstElementChild, null)
+  assert_equals(parentEl.lastElementChild, null)
+})
+]]></script>
+</body>
+</html>
diff --git a/tests/wpt/dom/nodes/Element-childElement-null.html b/tests/wpt/dom/nodes/Element-childElement-null.html
new file mode 100644
index 00000000..1863a41d
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-childElement-null.html
@@ -0,0 +1,15 @@
+<!DOCTYPE HTML>
+<meta charset=utf-8>
+<title>Null test</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<h1>Test of firstElementChild and lastChildElement returning null</h1>
+<div id="log"></div>
+<p id="parentEl" style="font-weight:bold;">Test.</p>
+<script>
+test(function() {
+  var parentEl = document.getElementById("parentEl")
+  assert_equals(parentEl.firstElementChild, null)
+  assert_equals(parentEl.lastElementChild, null)
+})
+</script>
diff --git a/tests/wpt/dom/nodes/Element-childElementCount-dynamic-add-svg.svg b/tests/wpt/dom/nodes/Element-childElementCount-dynamic-add-svg.svg
new file mode 100644
index 00000000..d149f1ea
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-childElementCount-dynamic-add-svg.svg
@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg"
+     xmlns:h="http://www.w3.org/1999/xhtml"
+     version="1.1"
+     width="100%" height="100%" viewBox="0 0 400 400">
+<title>Dynamic Adding of Elements</title>
+<h:script src="/resources/testharness.js"/>
+<h:script src="/resources/testharnessreport.js"/>
+
+<text x="200" y="40" font-size="25" fill="black" text-anchor="middle">Test of Dynamic Adding of Elements</text>
+<text id="parentEl" x="200" y="70" font-size="20" fill="black" text-anchor="middle">The result of this test is
+<tspan id="first_element_child" font-weight="bold">unknown.</tspan></text>
+
+<h:script><![CDATA[
+test(function() {
+  var parentEl = document.getElementById("parentEl");
+  var newChild = document.createElementNS("http://www.w3.org/2000/svg", "tspan");
+  parentEl.appendChild(newChild);
+  assert_equals(parentEl.childElementCount, 2)
+})
+]]></h:script>
+</svg>
diff --git a/tests/wpt/dom/nodes/Element-childElementCount-dynamic-add-xhtml.xhtml b/tests/wpt/dom/nodes/Element-childElementCount-dynamic-add-xhtml.xhtml
new file mode 100644
index 00000000..c97ed196
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-childElementCount-dynamic-add-xhtml.xhtml
@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<html xmlns="http://www.w3.org/1999/xhtml">
+<head>
+<title>Dynamic Adding of Elements</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+</head>
+<body>
+<h1>Test of Dynamic Adding of Elements</h1>
+<div id="log"></div>
+<p id="parentEl">The result of this test is
+<span id="first_element_child" style="font-weight:bold;">logged above.</span></p>
+<script><![CDATA[
+test(function() {
+  var parentEl = document.getElementById("parentEl");
+  var newChild = document.createElement("span");
+  parentEl.appendChild(newChild);
+  assert_equals(parentEl.childElementCount, 2)
+})
+]]></script>
+</body>
+</html>
diff --git a/tests/wpt/dom/nodes/Element-childElementCount-dynamic-add.html b/tests/wpt/dom/nodes/Element-childElementCount-dynamic-add.html
new file mode 100644
index 00000000..3e7490b2
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-childElementCount-dynamic-add.html
@@ -0,0 +1,17 @@
+<!DOCTYPE HTML>
+<meta charset=utf-8>
+<title>Dynamic Adding of Elements</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<h1>Test of Dynamic Adding of Elements</h1>
+<div id="log"></div>
+<p id="parentEl">The result of this test is
+<span id="first_element_child" style="font-weight:bold;">logged above.</span></p>
+<script>
+test(function() {
+  var parentEl = document.getElementById("parentEl");
+  var newChild = document.createElement("span");
+  parentEl.appendChild(newChild);
+  assert_equals(parentEl.childElementCount, 2)
+})
+</script>
diff --git a/tests/wpt/dom/nodes/Element-childElementCount-dynamic-remove-svg.svg b/tests/wpt/dom/nodes/Element-childElementCount-dynamic-remove-svg.svg
new file mode 100644
index 00000000..bf99de65
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-childElementCount-dynamic-remove-svg.svg
@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg"
+     xmlns:h="http://www.w3.org/1999/xhtml"
+     version="1.1"
+     width="100%" height="100%" viewBox="0 0 400 400">
+<title>Dynamic Removal of Elements</title>
+<h:script src="/resources/testharness.js"/>
+<h:script src="/resources/testharnessreport.js"/>
+
+<text x="200" y="40" font-size="25" fill="black" text-anchor="middle">Test of Dynamic Removal of Elements</text>
+<text id="parentEl" x="200" y="70" font-size="20" fill="black" text-anchor="middle">The result of this test is
+<tspan id="first_element_child" font-weight="bold">unknown.</tspan><tspan id="last_element_child"> </tspan></text>
+
+<h:script><![CDATA[
+test(function() {
+  var parentEl = document.getElementById("parentEl");
+  var lec = parentEl.lastElementChild;
+  parentEl.removeChild(lec);
+  assert_equals(parentEl.childElementCount, 1)
+})
+]]></h:script>
+</svg>
diff --git a/tests/wpt/dom/nodes/Element-childElementCount-dynamic-remove-xhtml.xhtml b/tests/wpt/dom/nodes/Element-childElementCount-dynamic-remove-xhtml.xhtml
new file mode 100644
index 00000000..f0009b0a
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-childElementCount-dynamic-remove-xhtml.xhtml
@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<html xmlns="http://www.w3.org/1999/xhtml">
+<head>
+<title>Dynamic Removal of Elements</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+</head>
+<body>
+<h1>Test of Removal Adding of Elements</h1>
+<div id="log"></div>
+<p id="parentEl">The result of this test is
+<span id="first_element_child" style="font-weight:bold;">logged above.</span><span id="last_element_child"> </span></p>
+<script><![CDATA[
+test(function() {
+  var parentEl = document.getElementById("parentEl");
+  var lec = parentEl.lastElementChild;
+  parentEl.removeChild(lec);
+  assert_equals(parentEl.childElementCount, 1)
+})
+]]></script>
+</body>
+</html>
diff --git a/tests/wpt/dom/nodes/Element-childElementCount-dynamic-remove.html b/tests/wpt/dom/nodes/Element-childElementCount-dynamic-remove.html
new file mode 100644
index 00000000..3f7e7c7e
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-childElementCount-dynamic-remove.html
@@ -0,0 +1,17 @@
+<!DOCTYPE HTML>
+<meta charset=utf-8>
+<title>Dynamic Removal of Elements</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<h1>Test of Dynamic Removal of Elements</h1>
+<div id="log"></div>
+<p id="parentEl">The result of this test is
+<span id="first_element_child" style="font-weight:bold;">unknown.</span><span id="last_element_child"> </span></p>
+<script>
+test(function() {
+  var parentEl = document.getElementById("parentEl");
+  var lec = parentEl.lastElementChild;
+  parentEl.removeChild(lec);
+  assert_equals(parentEl.childElementCount, 1)
+})
+</script>
diff --git a/tests/wpt/dom/nodes/Element-childElementCount-nochild-svg.svg b/tests/wpt/dom/nodes/Element-childElementCount-nochild-svg.svg
new file mode 100644
index 00000000..8ba57436
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-childElementCount-nochild-svg.svg
@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg"
+     xmlns:h="http://www.w3.org/1999/xhtml"
+     version="1.1"
+     width="100%" height="100%" viewBox="0 0 400 400">
+<title>childElementCount</title>
+<h:script src="/resources/testharness.js"/>
+<h:script src="/resources/testharnessreport.js"/>
+
+<text x="200" y="40" font-size="25" fill="black" text-anchor="middle">Test of childElementCount with No Child Element Nodes</text>
+<text id="parentEl" x="200" y="70" font-size="20" fill="black" text-anchor="middle" font-weight="bold">Test</text>
+
+<h:script><![CDATA[
+test(function() {
+  var parentEl = document.getElementById("parentEl")
+  assert_equals(parentEl.childElementCount, 0)
+})
+]]></h:script>
+</svg>
diff --git a/tests/wpt/dom/nodes/Element-childElementCount-nochild-xhtml.xhtml b/tests/wpt/dom/nodes/Element-childElementCount-nochild-xhtml.xhtml
new file mode 100644
index 00000000..f567a20c
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-childElementCount-nochild-xhtml.xhtml
@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<html xmlns="http://www.w3.org/1999/xhtml">
+<head>
+<title>childElementCount without Child Element Nodes</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+</head>
+<body>
+<h1>Test of childElementCount with No Child Element Nodes</h1>
+<div id="log"></div>
+<p id="parentEl" style="font-weight:bold;">Test.</p>
+<script><![CDATA[
+test(function() {
+  var parentEl = document.getElementById("parentEl")
+  assert_equals(parentEl.childElementCount, 0)
+})
+]]></script>
+</body>
+</html>
diff --git a/tests/wpt/dom/nodes/Element-childElementCount-nochild.html b/tests/wpt/dom/nodes/Element-childElementCount-nochild.html
new file mode 100644
index 00000000..fb52fb20
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-childElementCount-nochild.html
@@ -0,0 +1,14 @@
+<!DOCTYPE HTML>
+<meta charset=utf-8>
+<title>childElementCount without Child Element Nodes</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<h1>Test of childElementCount with No Child Element Nodes</h1>
+<div id="log"></div>
+<p id="parentEl" style="font-weight:bold;">Test.</p>
+<script>
+test(function() {
+  var parentEl = document.getElementById("parentEl")
+  assert_equals(parentEl.childElementCount, 0)
+})
+</script>
diff --git a/tests/wpt/dom/nodes/Element-childElementCount-svg.svg b/tests/wpt/dom/nodes/Element-childElementCount-svg.svg
new file mode 100644
index 00000000..ff93eff6
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-childElementCount-svg.svg
@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg"
+     xmlns:h="http://www.w3.org/1999/xhtml"
+     version="1.1"
+     width="100%" height="100%" viewBox="0 0 400 400">
+<title>childElementCount</title>
+<h:script src="/resources/testharness.js"/>
+<h:script src="/resources/testharnessreport.js"/>
+
+<text x="200" y="40" font-size="25" fill="black" text-anchor="middle">Test of childElementCount</text>
+<text id="parentEl" x="200" y="70" font-size="20" fill="black" text-anchor="middle">The result of <tspan id="first_element_child"><tspan>this</tspan> <tspan>test</tspan></tspan> is
+<tspan id="middle_element_child" font-weight="bold">unknown.</tspan>
+
+
+
+<tspan id="last_element_child" style="display:none;">fnord</tspan> </text>
+
+<h:script><![CDATA[
+test(function() {
+  var parentEl = document.getElementById("parentEl")
+  assert_true("childElementCount" in parentEl)
+  assert_equals(parentEl.childElementCount, 3)
+})
+]]></h:script>
+</svg>
diff --git a/tests/wpt/dom/nodes/Element-childElementCount-xhtml.xhtml b/tests/wpt/dom/nodes/Element-childElementCount-xhtml.xhtml
new file mode 100644
index 00000000..6b719ff7
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-childElementCount-xhtml.xhtml
@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<html xmlns="http://www.w3.org/1999/xhtml">
+<head>
+<title>childElementCount</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+</head>
+<body>
+<h1>Test of childElementCount</h1>
+<div id="log"></div>
+<p id="parentEl">The result of <span id="first_element_child"><span>this</span> <span>test</span></span> is
+<span id="middle_element_child" style="font-weight:bold;">unknown.</span>
+
+
+
+<span id="last_element_child" style="display:none;">fnord</span> </p>
+<script><![CDATA[
+test(function() {
+  var parentEl = document.getElementById("parentEl")
+  assert_true("childElementCount" in parentEl)
+  assert_equals(parentEl.childElementCount, 3)
+})
+]]></script>
+</body>
+</html>
diff --git a/tests/wpt/dom/nodes/Element-childElementCount.html b/tests/wpt/dom/nodes/Element-childElementCount.html
new file mode 100644
index 00000000..8cfe567f
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-childElementCount.html
@@ -0,0 +1,20 @@
+<!DOCTYPE HTML>
+<meta charset=utf-8>
+<title>childElementCount</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<h1>Test of childElementCount</h1>
+<div id="log"></div>
+<p id="parentEl">The result of <span id="first_element_child"><span>this</span> <span>test</span></span> is
+<span id="middle_element_child" style="font-weight:bold;">given above.</span>
+
+
+
+<span id="last_element_child" style="display:none;">fnord</span> </p>
+<script>
+test(function() {
+  var parentEl = document.getElementById("parentEl")
+  assert_true("childElementCount" in parentEl)
+  assert_equals(parentEl.childElementCount, 3)
+})
+</script>
diff --git a/tests/wpt/dom/nodes/Element-children.html b/tests/wpt/dom/nodes/Element-children.html
new file mode 100644
index 00000000..c0210f96
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-children.html
@@ -0,0 +1,58 @@
+<!DOCTYPE html>
+<title>HTMLCollection edge cases</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<div id="log"></div>
+<div id="test"><img><img id=foo><img id=foo><img name="bar"></div>
+<script>
+setup(function() {
+  // Add some non-HTML elements in there to test what happens with those.
+  var container = document.getElementById("test");
+  var child = document.createElementNS("", "img");
+  child.setAttribute("id", "baz");
+  container.appendChild(child);
+
+  child = document.createElementNS("", "img");
+  child.setAttribute("name", "qux");
+  container.appendChild(child);
+});
+
+test(function() {
+  var container = document.getElementById("test");
+  var result = container.children.item("foo");
+  assert_true(result instanceof Element, "Expected an Element.");
+  assert_false(result.hasAttribute("id"), "Expected the IDless Element.")
+})
+
+test(function() {
+  var container = document.getElementById("test");
+  var list = container.children;
+  var result = [];
+  for (var p in list) {
+    if (list.hasOwnProperty(p)) {
+      result.push(p);
+    }
+  }
+  assert_array_equals(result, ['0', '1', '2', '3', '4', '5']);
+  result = Object.getOwnPropertyNames(list);
+  assert_array_equals(result, ['0', '1', '2', '3', '4', '5', 'foo', 'bar', 'baz']);
+
+  // Mapping of exposed names to their indices in the list.
+  var exposedNames = { 'foo': 1, 'bar': 3, 'baz': 4 };
+  for (var exposedName in exposedNames) {
+    assert_true(exposedName in list);
+    assert_true(list.hasOwnProperty(exposedName));
+    assert_equals(list[exposedName], list.namedItem(exposedName));
+    assert_equals(list[exposedName], list.item(exposedNames[exposedName]));
+    assert_true(list[exposedName] instanceof Element);
+  }
+
+  var unexposedNames = ['qux'];
+  for (var unexposedName of unexposedNames) {
+    assert_false(unexposedName in list);
+    assert_false(list.hasOwnProperty(unexposedName));
+    assert_equals(list[unexposedName], undefined);
+    assert_equals(list.namedItem(unexposedName), null);
+  }
+});
+</script>
diff --git a/tests/wpt/dom/nodes/Element-firstElementChild-entity-xhtml.xhtml b/tests/wpt/dom/nodes/Element-firstElementChild-entity-xhtml.xhtml
new file mode 100644
index 00000000..f28005e9
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-firstElementChild-entity-xhtml.xhtml
@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
+        "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"
+[
+<!ENTITY tree "<span id='first_element_child' style='font-weight:bold;'>unknown.</span>">
+]>
+<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
+<head>
+<title>Entity References</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+</head>
+<body>
+<h1>Test of Entity References</h1>
+<div id="log"></div>
+<p id="parentEl">The result of this test is &tree;</p>
+<script><![CDATA[
+test(function() {
+  var parentEl = document.getElementById("parentEl")
+  var fec = parentEl.firstElementChild;
+  assert_true(!!fec)
+  assert_equals(fec.nodeType, 1)
+  assert_equals(fec.getAttribute("id"), "first_element_child")
+})
+]]></script>
+</body>
+</html>
diff --git a/tests/wpt/dom/nodes/Element-firstElementChild-entity.svg b/tests/wpt/dom/nodes/Element-firstElementChild-entity.svg
new file mode 100644
index 00000000..3a20ea79
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-firstElementChild-entity.svg
@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd"
+[
+<!ENTITY tree "<tspan id='first_element_child' font-weight='bold'>unknown.</tspan>">
+]>
+<svg xmlns="http://www.w3.org/2000/svg"
+     xmlns:h="http://www.w3.org/1999/xhtml"
+     version="1.1"
+     width="100%" height="100%" viewBox="0 0 400 400">
+<title>Entity References</title>
+<h:script src="/resources/testharness.js"/>
+<h:script src="/resources/testharnessreport.js"/>
+
+<text x="200" y="40" font-size="25" fill="black" text-anchor="middle">Test of Entity References</text>
+<text id="parentEl" x="200" y="70" font-size="20" fill="black" text-anchor="middle">The result of this test is &tree;</text>
+
+<h:script><![CDATA[
+test(function() {
+  var parentEl = document.getElementById("parentEl")
+  var fec = parentEl.firstElementChild;
+  assert_true(!!fec)
+  assert_equals(fec.nodeType, 1)
+  assert_equals(fec.getAttribute("id"), "first_element_child")
+})
+]]></h:script>
+</svg>
diff --git a/tests/wpt/dom/nodes/Element-firstElementChild-namespace-svg.svg b/tests/wpt/dom/nodes/Element-firstElementChild-namespace-svg.svg
new file mode 100644
index 00000000..d42c0877
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-firstElementChild-namespace-svg.svg
@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg"
+     xmlns:h="http://www.w3.org/1999/xhtml"
+     xmlns:pickle="http://ns.example.org/pickle"
+     version="1.1"
+     width="100%" height="100%" viewBox="0 0 400 400">
+<title>firstElementChild with namespaces</title>
+<h:script src="/resources/testharness.js"/>
+<h:script src="/resources/testharnessreport.js"/>
+
+<text x="200" y="40" font-size="25" fill="black" text-anchor="middle">Test of firstElementChild with namespaces</text>
+<g id="parentEl">
+  <pickle:dill id="first_element_child"/>
+</g>
+
+<h:script><![CDATA[
+test(function() {
+  var parentEl = document.getElementById("parentEl");
+  var fec = parentEl.firstElementChild;
+  assert_true(!!fec)
+  assert_equals(fec.nodeType, 1)
+  assert_equals(fec.getAttribute("id"), "first_element_child")
+  assert_equals(fec.localName, "dill")
+})
+]]></h:script>
+</svg>
diff --git a/tests/wpt/dom/nodes/Element-firstElementChild-namespace-xhtml.xhtml b/tests/wpt/dom/nodes/Element-firstElementChild-namespace-xhtml.xhtml
new file mode 100644
index 00000000..29441d27
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-firstElementChild-namespace-xhtml.xhtml
@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<html xmlns="http://www.w3.org/1999/xhtml"
+      xmlns:pickle="http://ns.example.org/pickle">
+<head>
+<title>firstElementChild with namespaces</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+</head>
+<body>
+<h1>Test of firstElementChild with namespaces</h1>
+<div id="parentEl">
+  <pickle:dill id="first_element_child"/>
+</div>
+<div id="log"></div>
+<p id="parentEl">The result of this test is
+<span id="first_element_child" style="font-weight:bold;">logged above.</span></p>
+<script><![CDATA[
+test(function() {
+  var parentEl = document.getElementById("parentEl");
+  var fec = parentEl.firstElementChild;
+  assert_true(!!fec)
+  assert_equals(fec.nodeType, 1)
+  assert_equals(fec.getAttribute("id"), "first_element_child")
+  assert_equals(fec.localName, "dill")
+})
+]]></script>
+</body>
+</html>
diff --git a/tests/wpt/dom/nodes/Element-firstElementChild-namespace.html b/tests/wpt/dom/nodes/Element-firstElementChild-namespace.html
new file mode 100644
index 00000000..629deab3
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-firstElementChild-namespace.html
@@ -0,0 +1,21 @@
+<!DOCTYPE HTML>
+<meta charset=utf-8>
+<title>firstElementChild with namespaces</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<h1>Test of firstElementChild with namespaces</h1>
+<div id="log"></div>
+<p id="parentEl">The result of this test is a unknown.</p>
+<script>
+test(function() {
+  var parentEl = document.getElementById("parentEl")
+  var el = document.createElementNS("http://ns.example.org/pickle", "pickle:dill")
+  el.setAttribute("id", "first_element_child")
+  parentEl.appendChild(el)
+  var fec = parentEl.firstElementChild
+  assert_true(!!fec)
+  assert_equals(fec.nodeType, 1)
+  assert_equals(fec.getAttribute("id"), "first_element_child")
+  assert_equals(fec.localName, "dill")
+})
+</script>
diff --git a/tests/wpt/dom/nodes/Element-firstElementChild-svg.svg b/tests/wpt/dom/nodes/Element-firstElementChild-svg.svg
new file mode 100644
index 00000000..359c5b82
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-firstElementChild-svg.svg
@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg"
+     xmlns:h="http://www.w3.org/1999/xhtml"
+     version="1.1"
+     width="100%" height="100%" viewBox="0 0 400 400">
+<title>firstElementChild</title>
+<h:script src="/resources/testharness.js"/>
+<h:script src="/resources/testharnessreport.js"/>
+
+<text x="200" y="40" font-size="25" fill="black" text-anchor="middle">Test of firstElementChild</text>
+<text id="parentEl" x="200" y="70" font-size="20" fill="black" text-anchor="middle">The result of this test is
+<tspan id="first_element_child" font-weight="bold">unknown.</tspan></text>
+
+<h:script><![CDATA[
+test(function() {
+  var parentEl = document.getElementById("parentEl");
+  var fec = parentEl.firstElementChild;
+  assert_true(!!fec)
+  assert_equals(fec.nodeType, 1)
+  assert_equals(fec.getAttribute("id"), "first_element_child")
+})
+]]></h:script>
+</svg>
diff --git a/tests/wpt/dom/nodes/Element-firstElementChild-xhtml.xhtml b/tests/wpt/dom/nodes/Element-firstElementChild-xhtml.xhtml
new file mode 100644
index 00000000..302052b0
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-firstElementChild-xhtml.xhtml
@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<html xmlns="http://www.w3.org/1999/xhtml">
+<head>
+<title>firstElementChild</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+</head>
+<body>
+<h1>Test of firstElementChild</h1>
+<div id="log"></div>
+<p id="parentEl">The result of this test is
+<span id="first_element_child" style="font-weight:bold;">logged above.</span></p>
+<script><![CDATA[
+test(function() {
+  var parentEl = document.getElementById("parentEl");
+  var fec = parentEl.firstElementChild;
+  assert_true(!!fec)
+  assert_equals(fec.nodeType, 1)
+  assert_equals(fec.getAttribute("id"), "first_element_child")
+})
+]]></script>
+</body>
+</html>
diff --git a/tests/wpt/dom/nodes/Element-firstElementChild.html b/tests/wpt/dom/nodes/Element-firstElementChild.html
new file mode 100644
index 00000000..12a0c594
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-firstElementChild.html
@@ -0,0 +1,18 @@
+<!DOCTYPE HTML>
+<meta charset=utf-8>
+<title>firstElementChild</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<h1>Test of firstElementChild</h1>
+<div id="log"></div>
+<p id="parentEl">The result of this test is
+<span id="first_element_child" style="font-weight:bold;">logged above.</span></p>
+<script>
+test(function() {
+  var parentEl = document.getElementById("parentEl");
+  var fec = parentEl.firstElementChild;
+  assert_true(!!fec)
+  assert_equals(fec.nodeType, 1)
+  assert_equals(fec.getAttribute("id"), "first_element_child")
+})
+</script>
diff --git a/tests/wpt/dom/nodes/Element-getElementsByClassName.html b/tests/wpt/dom/nodes/Element-getElementsByClassName.html
new file mode 100644
index 00000000..bc87b05d
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-getElementsByClassName.html
@@ -0,0 +1,43 @@
+<!DOCTYPE html>
+<title>Element.getElementsByClassName</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<div id="log"></div>
+<script>
+test(function() {
+  var a = document.createElement("a"), b = document.createElement("b")
+  b.className = "foo"
+  a.appendChild(b)
+  var list = a.getElementsByClassName("foo")
+  assert_array_equals(list, [b])
+  var secondList = a.getElementsByClassName("foo")
+  assert_true(list === secondList || list !== secondList, "Caching is allowed.")
+}, "getElementsByClassName should work on disconnected subtrees.")
+
+test(function() {
+  var list = document.getElementsByClassName("foo")
+  assert_false(list instanceof NodeList, "NodeList")
+  assert_true(list instanceof HTMLCollection, "HTMLCollection")
+}, "Interface should be correct.")
+
+test(function() {
+  var a = document.createElement("a");
+  var b = document.createElement("b");
+  var c = document.createElement("c");
+  b.className = "foo";
+  document.body.appendChild(a);
+  this.add_cleanup(function() {document.body.removeChild(a)});
+  a.appendChild(b);
+
+  var l = a.getElementsByClassName("foo");
+  assert_true(l instanceof HTMLCollection);
+  assert_equals(l.length, 1);
+
+  c.className = "foo";
+  a.appendChild(c);
+  assert_equals(l.length, 2);
+
+  a.removeChild(c);
+  assert_equals(l.length, 1);
+}, "getElementsByClassName() should be a live collection");
+</script>
diff --git a/tests/wpt/dom/nodes/Element-getElementsByTagName-change-document-HTMLNess-iframe.xml b/tests/wpt/dom/nodes/Element-getElementsByTagName-change-document-HTMLNess-iframe.xml
new file mode 100644
index 00000000..f3f286ea
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-getElementsByTagName-change-document-HTMLNess-iframe.xml
@@ -0,0 +1 @@
+<root/>
diff --git a/tests/wpt/dom/nodes/Element-getElementsByTagName-change-document-HTMLNess.html b/tests/wpt/dom/nodes/Element-getElementsByTagName-change-document-HTMLNess.html
new file mode 100644
index 00000000..c41ee2e8
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-getElementsByTagName-change-document-HTMLNess.html
@@ -0,0 +1,51 @@
+<!doctype html>
+<meta charset=utf-8>
+<title></title>
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<iframe src="Element-getElementsByTagName-change-document-HTMLNess-iframe.xml"></iframe>
+<script>
+  setup({ single_test: true });
+  onload = function() {
+    var parent = document.createElement("div");
+    var child1 = document.createElementNS("http://www.w3.org/1999/xhtml", "a");
+    child1.textContent = "xhtml:a";
+    var child2 = document.createElementNS("http://www.w3.org/1999/xhtml", "A");
+    child2.textContent = "xhtml:A";
+    var child3 = document.createElementNS("", "a");
+    child3.textContent = "a";
+    var child4 = document.createElementNS("", "A");
+    child4.textContent = "A";
+
+    parent.appendChild(child1);
+    parent.appendChild(child2);
+    parent.appendChild(child3);
+    parent.appendChild(child4);
+
+    var list = parent.getElementsByTagName("A");
+    assert_array_equals(list, [child1, child4],
+      "In an HTML document, should lowercase the tagname passed in for HTML " +
+      "elements only");
+
+    frames[0].document.documentElement.appendChild(parent);
+    assert_array_equals(list, [child1, child4],
+      "After changing document, should still be lowercasing for HTML");
+
+    assert_array_equals(parent.getElementsByTagName("A"),
+                        [child2, child4],
+      "New list with same root and argument should not be lowercasing now");
+
+    // Now reinsert all those nodes into the parent, to blow away caches.
+    parent.appendChild(child1);
+    parent.appendChild(child2);
+    parent.appendChild(child3);
+    parent.appendChild(child4);
+    assert_array_equals(list, [child1, child4],
+      "After blowing away caches, should still have the same list");
+
+    assert_array_equals(parent.getElementsByTagName("A"),
+                        [child2, child4],
+      "New list with same root and argument should still not be lowercasing");
+    done();
+  }
+</script>
diff --git a/tests/wpt/dom/nodes/Element-getElementsByTagName.html b/tests/wpt/dom/nodes/Element-getElementsByTagName.html
new file mode 100644
index 00000000..87c4fe93
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-getElementsByTagName.html
@@ -0,0 +1,30 @@
+<!DOCTYPE html>
+<meta charset=utf-8>
+<title>Element.getElementsByTagName</title>
+<link rel=help href="https://dom.spec.whatwg.org/#dom-element-getelementsbytagname">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="Document-Element-getElementsByTagName.js"></script>
+<div id="log"></div>
+<script>
+var element;
+setup(function() {
+  element = document.createElement("div");
+  element.appendChild(document.createTextNode("text"));
+  var p = element.appendChild(document.createElement("p"));
+  p.appendChild(document.createElement("a"))
+   .appendChild(document.createTextNode("link"));
+  p.appendChild(document.createElement("b"))
+   .appendChild(document.createTextNode("bold"));
+  p.appendChild(document.createElement("em"))
+   .appendChild(document.createElement("u"))
+   .appendChild(document.createTextNode("emphasized"));
+  element.appendChild(document.createComment("comment"));
+});
+
+test_getElementsByTagName(element, element);
+
+test(function() {
+  assert_array_equals(element.getElementsByTagName(element.localName), []);
+}, "Matching the context object");
+</script>
diff --git a/tests/wpt/dom/nodes/Element-getElementsByTagNameNS.html b/tests/wpt/dom/nodes/Element-getElementsByTagNameNS.html
new file mode 100644
index 00000000..f826afc3
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-getElementsByTagNameNS.html
@@ -0,0 +1,37 @@
+<!DOCTYPE html>
+<meta charset=utf-8>
+<title>Element.getElementsByTagNameNS</title>
+<link rel=help href="https://dom.spec.whatwg.org/#dom-element-getelementsbytagnamens">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="Document-Element-getElementsByTagNameNS.js"></script>
+<div id="log"></div>
+<script>
+var element;
+setup(function() {
+  element = document.createElement("div");
+  element.appendChild(document.createTextNode("text"));
+  var p = element.appendChild(document.createElement("p"));
+  p.appendChild(document.createElement("a"))
+   .appendChild(document.createTextNode("link"));
+  p.appendChild(document.createElement("b"))
+   .appendChild(document.createTextNode("bold"));
+  p.appendChild(document.createElement("em"))
+   .appendChild(document.createElement("u"))
+   .appendChild(document.createTextNode("emphasized"));
+  element.appendChild(document.createComment("comment"));
+});
+
+test_getElementsByTagNameNS(element, element);
+
+test(function() {
+  assert_array_equals(element.getElementsByTagNameNS("*", element.localName), []);
+}, "Matching the context object (wildcard namespace)");
+
+test(function() {
+  assert_array_equals(
+    element.getElementsByTagNameNS("http://www.w3.org/1999/xhtml",
+                                   element.localName),
+    []);
+}, "Matching the context object (specific namespace)");
+</script>
diff --git a/tests/wpt/dom/nodes/Element-lastElementChild-svg.svg b/tests/wpt/dom/nodes/Element-lastElementChild-svg.svg
new file mode 100644
index 00000000..1cec4a13
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-lastElementChild-svg.svg
@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg"
+     xmlns:h="http://www.w3.org/1999/xhtml"
+     version="1.1"
+     width="100%" height="100%" viewBox="0 0 400 400">
+<title>lastElementChild</title>
+<h:script src="/resources/testharness.js"/>
+<h:script src="/resources/testharnessreport.js"/>
+
+<text x="200" y="40" font-size="25" fill="black" text-anchor="middle">Test of lastElementChild</text>
+<text id="parentEl" x="200" y="70" font-size="20" fill="black" text-anchor="middle">The result of <tspan id="first_element_child">this test</tspan> is <tspan id="last_element_child" font-weight="bold">not</tspan> known.</text>
+
+<h:script><![CDATA[
+test(function() {
+  var parentEl = document.getElementById("parentEl");
+  var lec = parentEl.lastElementChild;
+  assert_true(!!lec)
+  assert_equals(lec.nodeType, 1)
+  assert_equals(lec.getAttribute("id"), "last_element_child")
+})
+]]></h:script>
+</svg>
diff --git a/tests/wpt/dom/nodes/Element-lastElementChild-xhtml.xhtml b/tests/wpt/dom/nodes/Element-lastElementChild-xhtml.xhtml
new file mode 100644
index 00000000..3150b92a
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-lastElementChild-xhtml.xhtml
@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<html xmlns="http://www.w3.org/1999/xhtml">
+<head>
+<title>firstElementChild</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+</head>
+<body>
+<h1>Test of firstElementChild</h1>
+<div id="log"></div>
+<p id="parentEl">The result of <span id="first_element_child">this test</span> is <span id="last_element_child" style="font-weight:bold;">logged</span> above.</p>
+<script><![CDATA[
+test(function() {
+  var parentEl = document.getElementById("parentEl");
+  var lec = parentEl.lastElementChild;
+  assert_true(!!lec)
+  assert_equals(lec.nodeType, 1)
+  assert_equals(lec.getAttribute("id"), "last_element_child")
+})
+]]></script>
+</body>
+</html>
diff --git a/tests/wpt/dom/nodes/Element-lastElementChild.html b/tests/wpt/dom/nodes/Element-lastElementChild.html
new file mode 100644
index 00000000..de7aebdf
--- /dev/null
+++ b/tests/wpt/dom/nodes/Element-lastElementChild.html
@@ -0,0 +1,17 @@
+<!DOCTYPE HTML>
+<meta charset=utf-8>
+<title>lastElementChild</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<h1>Test of lastElementChild</h1>
+<div id="log"></div>
+<p id="parentEl">The result of <span id="first_element_child">this test</span> is <span id="last_element_child" style="font-weight:bold;">logged</span> above.</p>
+<script>
+test(function() {
+  var parentEl = document.getElementById("parentEl");
+  var lec = parentEl.lastElementChild;
+  assert_true(!!lec)
+  assert_equals(lec.nodeType, 1)
+  assert_equals(lec.getAttribute("id"), "last_element_child")
+})
+</script>
diff --git a/tests/wpt/dom/nodes/ParentNode-children.html b/tests/wpt/dom/nodes/ParentNode-children.html
new file mode 100644
index 00000000..6621e7d9
--- /dev/null
+++ b/tests/wpt/dom/nodes/ParentNode-children.html
@@ -0,0 +1,27 @@
+<!DOCTYPE html>
+<meta charset=utf-8>
+<title>ParentNode.children</title>
+<link rel=help href="https://dom.spec.whatwg.org/#dom-parentnode-children">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<div id="log"></div>
+<div style="display: none">
+  <ul><li id='test'>1</li><li>2</li><li>3</li><li>4</li></ul>
+</div>
+<script>
+test(() => {
+  var node = document.getElementById("test");
+  var parentNode = node.parentNode;
+  var children = parentNode.children;
+  assert_true(children instanceof HTMLCollection);
+  var li = document.createElement("li");
+  assert_equals(children.length, 4);
+
+  parentNode.appendChild(li);
+  assert_equals(children.length, 5);
+
+  parentNode.removeChild(li);
+  assert_equals(children.length, 4);
+}, "ParentNode.children should be a live collection");
+</script>
+</html>