Step:
1) add page book mark to bookmark bar as
NAME :
FireBug
URL:
javascript:var firebug=document.createElement('script');firebug.setAttribute('src','http://getfirebug.com/releases/lite/1.2/firebug-lite-compressed.js');document.body.appendChild(firebug);(function(){if(window.firebug.version){firebug.init();}else{setTimeout(arguments.callee);}})();void(firebug);
After adding above book mark go to any page and click bookmark button "FireBug" on bookmark toolbar.It will open lite fire bug version in your page.
