var request = null; //holds request object
function createRequest() {
	try {
		request = new XMLHttpRequest(); //create a new XMLHttpRequest type request object
	} catch (trymicrosoft) {
		try {
			request = new ActiveXObject("Msxml2.XMLHTTP"); //create request for IE
		} catch (othermicrosoft) {
			try {
				request = new ActiveXObject("Microsoft.XMLHTTP"); //try another method to create request for IE
			} catch (failed) {
				request = null; //set request variable to null if we can't create the request object
			}
		}
	}
	if (request == null) //if it's still null, alert that request object couldn't be created.
	alert("Error creating request object.");
}