Facebook – How to block event invitations from a specific friends list

Easiest way is when you click decline on one of the person's event invitations, there is now a popup box which asks you to leave a message, and there's a link there to block event invites from that person.

The code you mentioned does not work as Facebook UI has changed and it will continue to change. Nevertheless,

javascript:var x=document.getElementsByTagName("input");for(var i=0;i<x.length;i++) {if (x[i].type == 'checkbox') {x[i].click();}}; alert('Done, all your friends have been selected');

_{Source: http://olivo.net/2011/04/how-to-invite-all-your-facebook-friends-to-an-event-at-once-code-has-changed/}

Should do the trick. It works on the currently selected list. The above should not break in any future builds though as the only input elements on the page are your Facebook friends.