How to insert JavaScript variable in Url.Action?

Question

JavaScript

There is such a script

function GetNewContact() {
           var oldId = document.getElementById("idOldContact").value;
           $.ajax({
               type: "GET",
               url: '@Url.Action("NewContacts", "Home", new { idOldContact =oldId})',
               success: function(msg){
                   $('#tableBody').append(msg);
               }
           })
       }

Actually, the problem is in the line

url: '@Url.Action("NewContacts", "Home", new { idOldContact =oldId})'

I don't know how to insert the value of the oldId variable. Now it gives an error.