User Agent: Mozilla/5.0 (Linux; Android 4.0.4; Galaxy Nexus Build/IMM76B) AppleWebKit/535.19 (KHTML, like Gecko) Chrome/18.0.1025.133 Mobile Safari/535.19 Steps to reproduce: METHOD 1: 1. Open Console 2. Enter this JS: while(true){ var foo=window.open("http://example.com"); } 3. Executing this will : + hang the whole firefox process. + Make all Closing options unusable except Task Manager + Use 1.5 GB Ram! METHOD 2: 1. Go to example.html attached. 3. visiting this html will : + hang the whole firefox process. + Make all Closing options unusable except Task Manager + Use 1.5 GB Ram! Actual results: 1. Whole Firefox was unresponsive 2. it was using 1.5 GB of Memory 3. i had to end it using TAsk amager but obviousle **many** don't know how to handle this. Expected results: Firefox should stop the script execution or prompt user asking wheather to stop it or not.