Count All attachments in Note

function Count_total_attachments_InNote() {

   try{

   var totalRecordCount = 0;

   var recordId = Xrm.Page.data.entity.getId().replace('{', '').replace('}', '');

   var req = new XMLHttpRequest();

   req.open("GET", Xrm.Page.context.getClientUrl() + "/api/data/v8.2/annotations?$select=annotationid,documentbody,filename,mimetype,subject&$filter=_objectid_value eq " + recordId + " and  isdocument eq true", true);

   req.setRequestHeader("OData-MaxVersion", "4.0");

   req.setRequestHeader("OData-Version", "4.0");

   req.setRequestHeader("Accept", "application/json");

   req.setRequestHeader("Content-Type", "application/json; charset=utf-8");

   req.onreadystatechange = function () {

       if (this.readyState === 4) {

           req.onreadystatechange = null;

           if (this.status === 200) {

               var results = JSON.parse(this.response);

               totalRecordCount = results.value.length;

   if(totalRecordCount>0)

   {

alert("Total attachments :" + totalRecordCount);

   }

   else{

   AlertMessage();

   }    

           }

           else {

               alert(this.statusText);

           }

       }

   }

   req.send();

   }

   catch(err)

   {

   alert(err.message);

   }

}

function AlertMessage()

{

alert("No Attachments Founds");

}