var xhr = null;
function request(callback,lien,variable,variable2) {

	if (xhr && xhr.readyState != 0) {
		xhr.abort(); // On annule la requête en cours !
	}
	 xhr = getXMLHttpRequest();

	xhr.onreadystatechange = function() {

		if (xhr.readyState == 4 && (xhr.status == 200 || xhr.status == 0)) {
			callback(xhr.responseText);	

		}
		else if (xhr.readyState < 4) {
			
		}
	};
	
	xhr.open("POST", lien, true);
	xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
	xhr.send("variable=" + variable + "&variable2=" + variable2);

}