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