docs: function updateTextArea(editor, checkForChange) {
  
      var html = $(editor.doc.body).html(),
        options = editor.options,
        updateTextAreaCallback = options.updateTextArea,
        $area = editor.$area;
  
      // Check for iframe change to avoid unnecessary firing
      // of potentially heavy updateTextArea callbacks.
      if (updateTextAreaCallback) {
        var sum = checksum(html);
        if (checkForChange && editor.frameChecksum == sum)
          return;
        editor.frameChecksum = sum;
      }
  
      // Convert the iframe html into textarea source code
      var code = updateTextAreaCallback ? updateTextAreaCallback(html) : html;
  
      // Update the textarea checksum
      if (options.updateFrame)
        editor.areaChecksum = checksum(code);
  
      // Update the textarea and trigger the change event
      if (code != $area.val()) {
        $area.val(code);
        $(editor).triggerHandler(CHANGE);
      }
  
    }