AJAX Response not working

//New line
$("#blank-add").on("click", function(){
var rowCount = $("#invoice_items >tbody >tr").length;
 
 $.ajax({
 type: "GET",
 "url" : "newrow.html",
 "dataType" : "html",
 "data" : {
             "id" : (rowCount+1)/2
 },
 success: function(data) {
 
var display= "<tr>";
var displayEnd ="</tr>";
        $("#invoice_items > tbody").append(display+data+displayEnd);
 }
 });