code: function( element, className ) {
              element = $.getElement( element );
  
              if (!element.className) {
                  element.className = className;
              } else if ( ( ' ' + element.className + ' ' ).
                  indexOf( ' ' + className + ' ' ) === -1 ) {
                  element.className += ' ' + className;
              }
          }
docs: Add the specified CSS class to the element if not present.
  @function
  @param {Element|String} element
  @param {String} className