diff --git a/src/browser/webapi/Document.zig b/src/browser/webapi/Document.zig
index ddb4c79a..a5e75bd7 100644
--- a/src/browser/webapi/Document.zig
+++ b/src/browser/webapi/Document.zig
@@ -53,6 +53,7 @@ _elements_by_id: std.StringHashMapUnmanaged(*Element) = .empty,
 _removed_ids: std.StringHashMapUnmanaged(void) = .empty,
 _active_element: ?*Element = null,
 _style_sheets: ?*StyleSheetList = null,
+_implementation: ?*DOMImplementation = null,
 _fonts: ?*FontFaceSet = null,
 _write_insertion_point: ?*Node = null,
 _script_created_parser: ?Parser.Streaming = null,
@@ -274,8 +275,11 @@ pub fn querySelectorAll(self: *Document, input: String, page: *Page) !*Selector.
     return Selector.querySelectorAll(self.asNode(), input.str(), page);
 }
 
-pub fn getImplementation(_: *const Document) DOMImplementation {
-    return .{};
+pub fn getImplementation(self: *Document, page: *Page) !*DOMImplementation {
+    if (self._implementation) |impl| return impl;
+    const impl = try page._factory.create(DOMImplementation{});
+    self._implementation = impl;
+    return impl;
 }
 
 pub fn createDocumentFragment(self: *Document, page: *Page) !*Node.DocumentFragment {
@@ -737,6 +741,7 @@ pub fn open(self: *Document, page: *Page) !*Document {
     self._elements_by_id.clearAndFree(page.arena);
     self._active_element = null;
     self._style_sheets = null;
+    self._implementation = null;
     self._ready_state = .loading;
 
     self._script_created_parser = Parser.Streaming.init(page.arena, doc_node, page);
diff --git a/src/browser/webapi/element/html/Input.zig b/src/browser/webapi/element/html/Input.zig
index 198d6015..94f5d092 100644
--- a/src/browser/webapi/element/html/Input.zig
+++ b/src/browser/webapi/element/html/Input.zig
@@ -125,6 +125,7 @@ pub fn setType(self: *Input, typ: []const u8, page: *Page) !void {
 }
 
 pub fn getValue(self: *const Input) []const u8 {
+    if (self._input_type == .file) return "";
     return self._value orelse self._default_value orelse switch (self._input_type) {
         .checkbox, .radio => "on",
         else => "",
@@ -132,8 +133,9 @@ pub fn getValue(self: *const Input) []const u8 {
 }
 
 pub fn setValue(self: *Input, value: []const u8, page: *Page) !void {
-    // File inputs cannot have their value set programmatically for security reasons
+    // File inputs: setting to empty string is a no-op, anything else throws
     if (self._input_type == .file) {
+        if (value.len == 0) return;
         return error.InvalidStateError;
     }
     // This should _not_ call setAttribute. It updates the current state only
@@ -866,9 +868,17 @@ pub const JsApi = struct {
         pub var class_id: bridge.ClassId = undefined;
     };
 
+    /// Handles [LegacyNullToEmptyString]: null → "" per HTML spec.
+    fn setValueFromJS(self: *Input, js_value: js.Value, page: *Page) !void {
+        if (js_value.isNull()) {
+            return self.setValue("", page);
+        }
+        return self.setValue(try js_value.toZig([]const u8), page);
+    }
+
     pub const onselectionchange = bridge.accessor(Input.getOnSelectionChange, Input.setOnSelectionChange, .{});
     pub const @"type" = bridge.accessor(Input.getType, Input.setType, .{});
-    pub const value = bridge.accessor(Input.getValue, Input.setValue, .{ .dom_exception = true });
+    pub const value = bridge.accessor(Input.getValue, setValueFromJS, .{ .dom_exception = true });
     pub const defaultValue = bridge.accessor(Input.getDefaultValue, Input.setDefaultValue, .{});
     pub const checked = bridge.accessor(Input.getChecked, Input.setChecked, .{});
     pub const defaultChecked = bridge.accessor(Input.getDefaultChecked, Input.setDefaultChecked, .{});