addLeadToCampaign.js

/*
 * JavaScript for custom Lead button to add the currently displayed lead
 * on the lead detail page to a hard-coded campaign.
 *
 * @see https://success.salesforce.com/answers?id=90630000000hZxyAAE
 */
// FIX:02 Changed API version from 27.0 to 29.0
{!REQUIRESCRIPT('/soap/ajax/29.0/connection.js')}

/* FIX:01 Removed due to unclear reason why this code is here
getDate = function(dateObj){
var day = dateObj.getDay() < 9 ? '0'+dateObj.getDay() : dateObj.getDay();
var month = dateObj.getMonth() < 9 ? '0'+dateObj.getMonth() : dateObj.getMonth();

return dateObj.getFullYear()+'-'+month+'-'+day;
}*/


var campaignMember = new sforce.SObject('CampaignMember');

campaignMember.CampaignId = '701i0000000abru';
campaignMember.LeadId = '{!Lead.Id}';
// FIX:03 Not sure why this is here. Specifying CampaignMember.LeadIs
//        shoudl be sufficient
//campaignMember.Lead = '{!Lead.Name}';
campaignMember.Status = 'Sent';



result = sforce.connection.create([campaignMember]);

if(result[0].success == 'true'){
    alert(campaignMember.CampaignId+' has been added to Campaign.');
}