Note: After saving, you have to bypass your browser's cache to see the changes. Internet Explorer: press Ctrl-F5, Mozilla: hold down Shift while clicking Reload (or press Ctrl-Shift-R), Opera/Konqueror: press F5, Safari: hold down Shift + Alt while clicking Reload, Chrome: hold down Shift while clicking Reload.
functionrollbackSummary(){varhasRollback=$("span.mw-rollback-link");if(hasRollback[0]){mw.util.addPortletLink('p-cactions','javascript:setRollbackSummary()',"rollback summary","ca-rollbacksummary","Set rollback link edit summary");}}$(rollbackSummary);functionsetRollbackSummary(){summary=prompt("Change the default rollback summary for rollback links on this page to:","");if(!summary){for(variindocument.links){if(document.links[i].href.indexOf('summary=')!=-1){document.links[i].href=document.links[i].href.substring(0,document.links[i].href.indexOf('summary=')-1);}}}else{summary="&summary="+encodeURIComponent(summary);for(variindocument.links){if(document.links[i].href.indexOf('action=rollback')!=-1){document.links[i].href+=summary;}}}}