function isTabHeading(node) {
    return node.tagName &&  (
      node.hasAttribute('tab-heading') ||
      node.hasAttribute('data-tab-heading') ||
      node.tagName.toLowerCase() === 'tab-heading' ||
      node.tagName.toLowerCase() === 'data-tab-heading'
    );
  }
@ngdoc directive
@name ui.bootstrap.tabs.directive:tabHeading
@restrict EA

@description
Creates an HTML heading for a {@link ui.bootstrap.tabs.directive:tab tab}. Must be placed as a child of a tab element.

@example
<example module="ui.bootstrap">
  <file name="index.html">
    <tabset>
      <tab>
        <tab-heading><b>HTML</b> in my titles?!</tab-heading>
        And some content, too!
      </tab>
      <tab>
        <tab-heading><i class="icon-heart"></i> Icon heading?!?</tab-heading>
        That's right.
      </tab>
    </tabset>
  </file>
</example>