Enable Try Dart to run on IE11.

site/try/src/html_to_text.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library trydart.htmlToText;
 
 import 'dart:math' show
     max;
 
 import 'dart:html' show
@@ skipping 14 matching lines @@
 
 /// Returns true if [node] is a block element, that is, not inline.
 bool isBlockElement(Node node) {
   if (node is! Element) return false;
   Element element = node;
 
   // TODO(ahe): Remove this line by changing code completion to avoid using a
   // div element.
   if (element.classes.contains('dart-code-completion')) return false;
 
-  return element.getComputedStyle().display != 'inline';
+  var display = element.getComputedStyle().display;
+  return display != 'inline' && display != 'none';
 }
 
 /// Writes the text of [root] to [buffer]. Keeps track of [selection] and
 /// returns the new anchorOffset from beginning of [buffer] or -1 if the
 /// selection isn't in [root].
 int htmlToText(Node root,
                StringBuffer buffer,
                TrySelection selection,
                {bool treatRootAsInline: false}) {
   int selectionOffset = -1;
@@ skipping 21 matching lines @@
 
     return WALKER_NEXT;
   });
 
   if (!treatRootAsInline && isBlockElement(root)) {
     buffer.write('\n');
   }
 
   return selectionOffset;
 }