clearIfNecessary = function(event) {
      var element = this;
      setTimeout(function() {
        var innerHTML = element.innerHTML.toLowerCase();
        if (innerHTML == "<p>&nbsp;</p>" ||
            innerHTML == "<p>&nbsp;</p><p>&nbsp;</p>") {
          element.innerHTML = "";
        }
      }, 0);
    }
IE and Opera leave an empty paragraph in the contentEditable element after clearing it

@param {Object} contentEditableElement The contentEditable element to observe for clearing events
@exaple
   wysihtml5.quirks.ensureProperClearing(myContentEditableElement);