This is the simple code that works

to select all ur friends in facebook

when u press enter

javascript:elms=document.getElementById(‘friends’).getElementsByTagName(‘li’);for(var fid in elms){if(typeof elms[fid] === ‘object’){fs.click(elms[fid]);}}

1. Go to your Event, Group or page and click “Invite People”.
2. Once the page has loaded you should see all of your friends, but they are not selected.
3. At this point, copy and paste the javascript code below into your Web browser’s address bar, then hit “Enter”.
4. If all goes well, it selects all of your friends!