cross-browser XMLHttpRequest instantiation

xmlHttpReq_init.js

var xmlHttp = createXmlHttpRequestObject();

function createXmlHttpRequestObject () {
	var xmlHttp;

	if (window.ActiveXObject) {
		try {
			xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
		} catch(e) {
			xmlHttp = false;
		}
	} else {
		try {
			xmlHttp = new XMLHttpRequest();
		} catch(e) {
			xmlHttp = false;
		}
	}

	if (!xmlHttp) {
		alert("Error creating the XMLHttpRequest object.");
	} else {
		return xmlHttp;
	}
}