Javascript injection asp mvc

I created a controller:

    [Authorize]
    [AcceptVerbs(HttpVerbs.Delete)]
    public ActionResult Delete(int id)
    {
        try
        {
            db.DeleteObject(db.AEROLINEA.FirstOrDefault(x => x.AEROLINEAID == id));
            db.SaveChanges();
        }
        catch { /* TODO:Display message*/ }

        return View();
    }

      

        
        
        
      

    

if i execute in firebug the following javascript who checked in can delete the airline even if it doesn't have delete permissions.

    var action = "/Airline/Delete/" + recordId;

    var request = new Sys.Net.WebRequest();
    request.set_httpVerb("DELETE");
    request.set_url(action);
    request.add_completed(deleteCompleted);
    request.invoke();

      

        
        
        
      

    

HOw can avoid this problem.