rem: callback = function() { }; 
add: callback = function() {}; 
context:         callback = function() {        };
meta: 3428	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/3428/dbe982e89ab58bfbdcacd8bff39712cf2f735085/selenium-remoterunner.js/buggy/src/main/resources/core/scripts/selenium-remoterunner.js