sdk/lib/html/dart2js/html_dart2js.dart

Index: sdk/lib/html/dart2js/html_dart2js.dart
diff --git a/sdk/lib/html/dart2js/html_dart2js.dart b/sdk/lib/html/dart2js/html_dart2js.dart
index 708bdb016ca2a9c401377247d8acbd598516f465..39841fb3ecc4c5ce3e2a5cd4ff9a7704f855b07d 100644
--- a/sdk/lib/html/dart2js/html_dart2js.dart
+++ b/sdk/lib/html/dart2js/html_dart2js.dart
@@ -28345,9 +28345,38 @@ class _DataAttributeMap implements Map<String, String> {
   bool get isNotEmpty => !isEmpty;
 
   // Helpers.
-  String _attr(String key) => 'data-$key';
+  String _attr(String key) => 'data-${_toHyphenedName(key)}'; // todo add hyphens where capitalized
   bool _matches(String key) => key.startsWith('data-');
-  String _strip(String key) => key.substring(5);
+  String _strip(String key) => _toCamelCase(key.substring(5)); // todo: capitalize and remove hyphens
+
+  /**
+   * Converts a string name with hyphens into an identifier, by removing hyphens
+   * and capitalizing the following letter. Optionally [startUppercase] to
+   * captialize the first letter.
+   */
+  String _toCamelCase(String hyphenedName, {bool startUppercase: false}) {
+    var segments = hyphenedName.split('-');
+    int start = startUppercase ? 0 : 1;
+    for (int i = start; i < segments.length; i++) {
+      var segment = segments[i];
+      if (segment.length > 0) {
+        // Character between 'a'..'z' mapped to 'A'..'Z'
+        segments[i] = '${segment[0].toUpperCase()}${segment.substring(1)}';
+      }
+    }
+    return segments.join('');
+  }
+
+  /** Reverse of [toCamelCase]. */
+  String _toHyphenedName(String word) {
+    var sb = new StringBuffer();
+    for (int i = 0; i < word.length; i++) {
+      var lower = word[i].toLowerCase();
+      if (word[i] != lower && i > 0) sb.write('-');
+      sb.write(lower);
+    }
+    return sb.toString();
+  }
 }
 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a