Placing a report in the IFrame with GUID as parameter

//Placing a report in the IFrame without asking for credentials

   //get guid of form
var guid= crmFormSubmit.crmFormSubmitId.value;
guid = guid.substring(1, guid.length -1)


var url = "http://server/ReportServer?/Myreport&rs:Command=Render&rc:Toolbar=false&Guid="+ guid;


document.getElementById('IFRAME_Report').src = url;