Basic Ajax Request

ajax.js

function ajaxRequest(target, method, params, callback, graph) {
	var xmlhttp=false;
	if (!xmlhttp && typeof XMLHttpRequest!='undefined') {
		try {
			xmlhttp = new XMLHttpRequest();
		} catch (e) {
			xmlhttp=false;
		}
	}
	if (!xmlhttp && window.createRequest) {
		try {
			xmlhttp = window.createRequest();
		} catch (e) {
			xmlhttp=false;
		}
	}

	xmlhttp.onreadystatechange = function() {
		if (xmlhttp.readyState == 4 && xmlhttp.status == 200) { 
			window[callback](xmlhttp.responseText);
		} else if (xmlhttp.status.toString().substring(0,1) == 3 || xmlhttp.status.toString().substring(0,1) == 4) {
			message('Die Anfrage lieferte kein Resultat.', true);
		}
	};
	
	xmlhttp.open(method, target, true);
	if ((method == 'POST' || method == 'post') && params.length > 0) {
		xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
		xmlhttp.setRequestHeader("Content-length", params.length);
		xmlhttp.setRequestHeader("Connection", "close");

		xmlhttp.send(params);
	} else {
		xmlhttp.send(null);
	}
}