diff --git a/src/browser/tests/range.html b/src/browser/tests/range.html
index 73a43ff7..c1fb901f 100644
--- a/src/browser/tests/range.html
+++ b/src/browser/tests/range.html
@@ -820,3 +820,137 @@
   });
 }
 </script>
+
+<script id=deleteContents_crossNode>
+{
+  // Test deleteContents across multiple sibling text nodes
+  const p = document.createElement('p');
+  p.appendChild(document.createTextNode('AAAA'));
+  p.appendChild(document.createTextNode('BBBB'));
+  p.appendChild(document.createTextNode('CCCC'));
+
+  testing.expectEqual(3, p.childNodes.length);
+  testing.expectEqual('AAAABBBBCCCC', p.textContent);
+
+  const range = document.createRange();
+  // Start at position 2 in first text node ("AA|AA")
+  range.setStart(p.childNodes[0], 2);
+  // End at position 2 in third text node ("CC|CC")
+  range.setEnd(p.childNodes[2], 2);
+
+  range.deleteContents();
+
+  // Should have truncated first node to "AA" and third node to "CC"
+  // Middle node should be removed
+  testing.expectEqual(2, p.childNodes.length);
+  testing.expectEqual('AA', p.childNodes[0].textContent);
+  testing.expectEqual('CC', p.childNodes[1].textContent);
+  testing.expectEqual('AACC', p.textContent);
+}
+</script>
+
+<script id=deleteContents_crossNode_partial>
+{
+  // Test deleteContents where start node is completely preserved
+  const p = document.createElement('p');
+  p.appendChild(document.createTextNode('KEEP'));
+  p.appendChild(document.createTextNode('DELETE'));
+  p.appendChild(document.createTextNode('PARTIAL'));
+
+  const range = document.createRange();
+  // Start at end of first text node
+  range.setStart(p.childNodes[0], 4);
+  // End in middle of third text node
+  range.setEnd(p.childNodes[2], 4);
+
+  range.deleteContents();
+
+  testing.expectEqual(2, p.childNodes.length);
+  testing.expectEqual('KEEP', p.childNodes[0].textContent);
+  testing.expectEqual('IAL', p.childNodes[1].textContent);
+  testing.expectEqual('KEEPIAL', p.textContent);
+}
+</script>
+
+<script id=extractContents_crossNode>
+{
+  // Test extractContents across multiple sibling text nodes
+  const p = document.createElement('p');
+  p.appendChild(document.createTextNode('AAAA'));
+  p.appendChild(document.createTextNode('BBBB'));
+  p.appendChild(document.createTextNode('CCCC'));
+
+  const range = document.createRange();
+  range.setStart(p.childNodes[0], 2);
+  range.setEnd(p.childNodes[2], 2);
+
+  const fragment = range.extractContents();
+
+  // Original should be truncated
+  testing.expectEqual(2, p.childNodes.length);
+  testing.expectEqual('AA', p.childNodes[0].textContent);
+  testing.expectEqual('CC', p.childNodes[1].textContent);
+
+  // Fragment should contain extracted content
+  testing.expectEqual(3, fragment.childNodes.length);
+  testing.expectEqual('AA', fragment.childNodes[0].textContent);
+  testing.expectEqual('BBBB', fragment.childNodes[1].textContent);
+  testing.expectEqual('CC', fragment.childNodes[2].textContent);
+}
+</script>
+
+<script id=cloneContents_crossNode>
+{
+  // Test cloneContents across multiple sibling text nodes
+  const p = document.createElement('p');
+  p.appendChild(document.createTextNode('AAAA'));
+  p.appendChild(document.createTextNode('BBBB'));
+  p.appendChild(document.createTextNode('CCCC'));
+
+  const range = document.createRange();
+  range.setStart(p.childNodes[0], 2);
+  range.setEnd(p.childNodes[2], 2);
+
+  const fragment = range.cloneContents();
+
+  // Original should be unchanged
+  testing.expectEqual(3, p.childNodes.length);
+  testing.expectEqual('AAAA', p.childNodes[0].textContent);
+  testing.expectEqual('BBBB', p.childNodes[1].textContent);
+  testing.expectEqual('CCCC', p.childNodes[2].textContent);
+
+  // Fragment should contain cloned content
+  testing.expectEqual(3, fragment.childNodes.length);
+  testing.expectEqual('AA', fragment.childNodes[0].textContent);
+  testing.expectEqual('BBBB', fragment.childNodes[1].textContent);
+  testing.expectEqual('CC', fragment.childNodes[2].textContent);
+}
+</script>
+
+<script id=deleteContents_crossNode_withElements>
+{
+  // Test deleteContents with mixed text and element nodes
+  const div = document.createElement('div');
+  div.appendChild(document.createTextNode('Start'));
+  const span = document.createElement('span');
+  span.textContent = 'Middle';
+  div.appendChild(span);
+  div.appendChild(document.createTextNode('End'));
+
+  testing.expectEqual(3, div.childNodes.length);
+
+  const range = document.createRange();
+  // Start in middle of first text node
+  range.setStart(div.childNodes[0], 2);
+  // End in middle of last text node
+  range.setEnd(div.childNodes[2], 1);
+
+  range.deleteContents();
+
+  // Should keep "St" from start, remove span, keep "nd" from end
+  testing.expectEqual(2, div.childNodes.length);
+  testing.expectEqual('St', div.childNodes[0].textContent);
+  testing.expectEqual('nd', div.childNodes[1].textContent);
+  testing.expectEqual('Stnd', div.textContent);
+}
+</script>
diff --git a/src/browser/webapi/MutationObserver.zig b/src/browser/webapi/MutationObserver.zig
index 9e1acbdc..5e066d17 100644
--- a/src/browser/webapi/MutationObserver.zig
+++ b/src/browser/webapi/MutationObserver.zig
@@ -69,6 +69,10 @@ pub fn observe(self: *MutationObserver, target: *Node, options: ObserveOptions,
         copied_options.attributeFilter = filter_copy;
     }
 
+    if (options.characterDataOldValue) {
+        copied_options.characterData = true;
+    }
+
     // Check if already observing this target
     for (self._observing.items) |*obs| {
         if (obs.target == target) {
@@ -274,6 +278,13 @@ pub const MutationRecord = struct {
         return self._target;
     }
 
+    pub fn getAttributeNamespace(self: *const MutationRecord) ?[]const u8 {
+        if (self._attribute_name != null) {
+            return "http://www.w3.org/1999/xhtml";
+        }
+        return null;
+    }
+
     pub fn getAttributeName(self: *const MutationRecord) ?[]const u8 {
         return self._attribute_name;
     }
@@ -310,6 +321,7 @@ pub const MutationRecord = struct {
         pub const @"type" = bridge.accessor(MutationRecord.getType, null, .{});
         pub const target = bridge.accessor(MutationRecord.getTarget, null, .{});
         pub const attributeName = bridge.accessor(MutationRecord.getAttributeName, null, .{});
+        pub const attributeNamespace = bridge.accessor(MutationRecord.getAttributeNamespace, null, .{});
         pub const oldValue = bridge.accessor(MutationRecord.getOldValue, null, .{});
         pub const addedNodes = bridge.accessor(MutationRecord.getAddedNodes, null, .{});
         pub const removedNodes = bridge.accessor(MutationRecord.getRemovedNodes, null, .{});
diff --git a/src/browser/webapi/Node.zig b/src/browser/webapi/Node.zig
index 03f7ac7f..b8bb1efd 100644
--- a/src/browser/webapi/Node.zig
+++ b/src/browser/webapi/Node.zig
@@ -652,9 +652,9 @@ pub fn getData(self: *const Node) []const u8 {
     };
 }
 
-pub fn setData(self: *Node, data: []const u8) void {
+pub fn setData(self: *Node, data: []const u8, page: *Page) !void {
     switch (self._type) {
-        .cdata => |c| c._data = data,
+        .cdata => |c| try c.setData(data, page),
         else => {},
     }
 }
diff --git a/src/browser/webapi/Range.zig b/src/browser/webapi/Range.zig
index 54f4f5a4..e8d08b84 100644
--- a/src/browser/webapi/Range.zig
+++ b/src/browser/webapi/Range.zig
@@ -357,7 +357,7 @@ pub fn deleteContents(self: *Range, page: *Page) !void {
                 u8,
                 &.{ text_data[0..self._proto._start_offset], text_data[self._proto._end_offset..] },
             );
-            self._proto._start_container.setData(new_text);
+            try self._proto._start_container.setData(new_text, page);
         } else {
             // Delete child nodes in range
             var offset = self._proto._start_offset;
@@ -371,8 +371,43 @@ pub fn deleteContents(self: *Range, page: *Page) !void {
         return;
     }
 
-    // Complex case: different containers - simplified implementation
-    // Just collapse the range for now
+    // Complex case: different containers
+    // Handle start container - if it's a text node, truncate it
+    if (self._proto._start_container.is(Node.CData)) |_| {
+        const text_data = self._proto._start_container.getData();
+        if (self._proto._start_offset < text_data.len) {
+            // Keep only the part before start_offset
+            const new_text = text_data[0..self._proto._start_offset];
+            try self._proto._start_container.setData(new_text, page);
+        }
+    }
+
+    // Handle end container - if it's a text node, truncate it
+    if (self._proto._end_container.is(Node.CData)) |_| {
+        const text_data = self._proto._end_container.getData();
+        if (self._proto._end_offset < text_data.len) {
+            // Keep only the part from end_offset onwards
+            const new_text = text_data[self._proto._end_offset..];
+            try self._proto._end_container.setData(new_text, page);
+        } else if (self._proto._end_offset == text_data.len) {
+            // If we're at the end, set to empty (will be removed if needed)
+            try self._proto._end_container.setData("", page);
+        }
+    }
+
+    // Remove nodes between start and end containers
+    // For now, handle the common case where they're siblings
+    if (self._proto._start_container.parentNode() == self._proto._end_container.parentNode()) {
+        var current = self._proto._start_container.nextSibling();
+        while (current != null and current != self._proto._end_container) {
+            const next = current.?.nextSibling();
+            if (current.?.parentNode()) |parent| {
+                _ = try parent.removeChild(current.?, page);
+            }
+            current = next;
+        }
+    }
+
     self.collapse(true);
 }
 
@@ -401,6 +436,39 @@ pub fn cloneContents(self: *const Range, page: *Page) !*DocumentFragment {
                 }
             }
         }
+    } else {
+        // Complex case: different containers
+        // Clone partial start container
+        if (self._proto._start_container.is(Node.CData)) |_| {
+            const text_data = self._proto._start_container.getData();
+            if (self._proto._start_offset < text_data.len) {
+                // Clone from start_offset to end of text
+                const cloned_text = text_data[self._proto._start_offset..];
+                const text_node = try page.createTextNode(cloned_text);
+                _ = try fragment.asNode().appendChild(text_node, page);
+            }
+        }
+
+        // Clone nodes between start and end containers (siblings case)
+        if (self._proto._start_container.parentNode() == self._proto._end_container.parentNode()) {
+            var current = self._proto._start_container.nextSibling();
+            while (current != null and current != self._proto._end_container) {
+                const cloned = try current.?.cloneNode(true, page);
+                _ = try fragment.asNode().appendChild(cloned, page);
+                current = current.?.nextSibling();
+            }
+        }
+
+        // Clone partial end container
+        if (self._proto._end_container.is(Node.CData)) |_| {
+            const text_data = self._proto._end_container.getData();
+            if (self._proto._end_offset > 0 and self._proto._end_offset <= text_data.len) {
+                // Clone from start to end_offset
+                const cloned_text = text_data[0..self._proto._end_offset];
+                const text_node = try page.createTextNode(cloned_text);
+                _ = try fragment.asNode().appendChild(text_node, page);
+            }
+        }
     }
 
     return fragment;