if(!fbs) return; 
        function topLevelHook(frame, type)        {			if (fbs.DBG_STEP) dumpToFileWithStack("topLevel type="+(type==0?"TOPLEVEL_START":"TOPLEVEL_END"), frame);  /*@explore*/        	if ( isSystemURL(frame.script.fileName) )        		return;            switch (type)            {                case TYPE_TOPLEVEL_START:                {                	var debuggr = fbs.findDebugger(frame);                	if (debuggr)                		debuggr.onTopLevelScript(null, 0, frame.script);					break;                }                case TYPE_TOPLEVEL_END:					break;            }        }
2454	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/2454/c4cde785872f9564974cbcb5f51250cbf9e542db/firebug-service.js/clean/extension/components/firebug-service.js