User Agent: Mozilla/5.0 (Windows NT 6.1; rv:7.0) Gecko/20100101 Firefox/7.0 Build ID: 20110928030855 Steps to reproduce: Firefox's build-in web developer tools are much useless compare to Chrome. We could do better. Some simple results: document.scripts document.images we got object HTMLCollection. document.scripts[0] document.images[0] we got object HTMLImageElement & object HTMLScriptElement. When click on it, show a lot detail. Chrome's console gave thing like: <img src="" alt=""> or <script type="text/javascripts" src=""></script> simple yet useful info. It should work better, in fact, firefox pick up so many "Chrome style" since Fx4, Chrome build-in developer tools is definitly we should learn from.