function getElementInnerHTML(element) {
  return genericPropertyGet(
      Methods.INNER_HTML_GETTER, element, 'innerHTML', function(html) {
        return typeof html == 'string';
      });
}
Returns a node's innerHTML property value without falling prey to things like
<form><input name="innerHTML"></form>. Equivalent to
`element.innerHTML`.
@param {!Element} element
@return {string}