ExtraRollbackLink

/* extra rollback links */
function CustomRollbacks() {
    var Buttons = [{ //Your buttons go here. You can copy and paste this to make more than three
        text: 'spam',
        title: 'Revert spam',
        summary: '[[Help:Spam|spam]]'
    }, {
        text: 'vandalism',
        title: 'Revert vandalism',
        summary: '[[Help:Vandalism|vandalism]]'
    }, {
        text: 'null',
        title: 'Revert with no summary',
        summary: ' ' //This one has no summary
    }];

    var list = document.getElementsByTagName('span');
    for(i in list) {
        if(list[i].className == 'mw-rollback-link') {
            var link = list[i];
            var rollback = link.innerHTML;
            for(j in Buttons) {
                var customlink = document.createElement('span');
                customlink.innerHTML = rollback;
                customlink.className = 'customrollback'; //we do this to avoid an infinite loop, because when we insert a <span> into the DOM, the list variable includes it
                customlink.getElementsByTagName('a')[0].title = Buttons[j].title;
                customlink.getElementsByTagName('a')[0].href += '&summary=' + Buttons[j].summary;
                customlink.getElementsByTagName('a')[0].innerHTML = Buttons[j].text;
                if(wgPageName == 'Special:RecentChanges' || wgPageName == 'Special:Contributions') {
                    link.parentElement.appendChild(customlink);
                    customlink.outerHTML = ' ' + customlink.outerHTML;
                }
                else { //assumes you're on history
                    link.parentElement.insertBefore(customlink, link.nextSibling);
                    customlink.outerHTML = ' | ' + customlink.outerHTML;
                }
            }
        }
    }
    for(i in list) { //why another one of these? we're fixing the class that we set to avoid an infinite loop
        if(list[i].className == 'customrollback') {
            list[i].className = 'mw-rollback-link';
        }
    }
}

addOnloadHook(CustomRollbacks);