JS: Cross-domain jQuery JSON AJAX alternative for IE

gistfile1.js

// The ajax.php file must also return header('Access-Control-Allow-Origin: *');

	if ($.browser.msie && window.XDomainRequest) {

		// Use Microsoft XDR
		var xdr = new XDomainRequest();
		xdr.open("POST", js_base_url + 'ajax?id='+id);
		xdr.onload = function () {
			var JSON = $.parseJSON(xdr.responseText);
			alert(JSON.response);
		};
		xdr.send();

	} else {

		$.ajax({
			type: 'POST',
			url: js_base_url + 'ajax',
			data: {id: id},
			dataType: 'json',
			success: function(data) {
				alert(data.response);
			}
		});

	}