function getXhr(){
var xhr = null;
if(window.ActiveXObject){
try {
xhr = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {
xhr = new ActiveXObject("Microsoft.XMLHTTP");
}
} else if(window.XMLHttpRequest) {
xhr = new XMLHttpRequest();
} else {
alert("Votre navigateur ne supporte pas les objets XMLHTTPRequest...");
xhr = false;
}
return xhr;
};