this.set(this.toArray().concat(classNameToAdd).join(' ')); 
this.set($A(this).concat(classNameToAdd).join(' ')); 
  add: function(classNameToAdd) {    if (this.include(classNameToAdd)) return;    this.set(this.toArray().concat(classNameToAdd).join(' '));  },
6445	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/6445/81ea0800bc8ad92d491743716cd489cad7333723/prototype.js/buggy/vendor/rails/actionpack/lib/action_view/helpers/javascripts/prototype.js