XMLHttpRequest.js

function XMLHttpRequest() {
	var progIDs = [
		"Msxml2.ServerXMLHTTP.6.0",
		"Msxml2.ServerXMLHTTP.5.0",
		"Msxml2.ServerXMLHTTP.4.0",
		"Msxml2.ServerXMLHTTP.3.0",
		"Msxml2.ServerXMLHTTP",
		"Microsoft.ServerXMLHTTP",
		"Msxml2.XMLHTTP.6.0",
		"Msxml2.XMLHTTP.5.0",
		"Msxml2.XMLHTTP.4.0",
		"Msxml2.XMLHTTP.3.0",
		"Msxml2.XMLHTTP",
		"Microsoft.XMLHTTP"
	];

	var i;
	for (i = 0; i < progIDs.length; ++i) {
		try {
			return new ActiveXObject(progIDs[i]);
		} catch (e) {
			if (i == progIDs.length - 1) {
				throw e;
			}
		}
	}
}