FetchXml concept not able to proceed non ie browsers

hi frnds,

      In my project am using fetchxml concept to retrieve datas from other entities.It works fine in ie browser.But when i use non ie browser its not working.

Below is my code

var opportunityid = Xrm.Page.data.entity.getId();
    if(opportunityid != null)
    {
var fetchXml =
"<fetch mapping='logical'>" +
   "<entity name='stagedetails'>" +
      "<attribute name='stagedetailsid' />" +
      "<attribute name='dardvt_proceedforreassessment' />" +
      "<attribute name='pricelist' />" +
      "<filter>" +
         "<condition attribute='opportunity' operator='eq' value='" + opportunityid + "'  />" +  
         "<condition attribute='status' operator='eq' value='0' />" +  
      "</filter>" +
   "</entity>" +
"</fetch>";
//so far i have no problem,.
var fetchedstage = CrmServiceToolkit.Fetch(fetchXml);/am getting problem here.It saying undefined error

Pls can any one give me the solution as soon as possible.Thanx in advance.

Arun Kumar G