xhr

if (window.XMLHttpRequest)
  {// code for IE7+, Firefox, Chrome, Opera, Safari
  xhr=new XMLHttpRequest();
  }
else
  {// code for IE6, IE5
  xhr=new ActiveXObject("Microsoft.XMLHTTP");
  }

    $(function() {
      var url = "http://www.google.com";
      $.ajax(url,
      {
         error:function (xhr, ajaxOptions, thrownError){
          alert(xhr.status);
           switch (xhr.status) {
              case 404:
                    // Desired Action.
              }
        }

    	 complete: function(xhr, statusText){
           alert(xhr.status);
   	 }
      }
   });
});