{!REQUIRESCRIPT('/soap/ajax/29.0/connection.js')}
{!REQUIRESCRIPT("/soap/ajax/29.0/apex.js")}

var newRecords = [];
var c = new sforce.SObject("Activity/Event");
c.id ="{!Campaign.Id }";
c.Community_Deleted__c = true;
newRecords.push(c);
result = sforce.connection.update(newRecords);
window.location.reload();