// CONSTRUCTION DE L'OBJET XMLHTTP
function createXhr()
{
	var xhr2 = null;
	 if (window.XMLHttpRequest) // Firefox et autres
	 {
	  xhr2 = new XMLHttpRequest();
	 }
	 else if (window.ActiveXObject) // Internet Explorer
	 {
	  try
	  {
	   xhr2 = new ActiveXObject("Microsoft.XMLHTTP" );
	  }
	  catch (e)
	  {
	   try
	   {
	    xhr2 = new ActiveXObject("Msxml2.XMLHTTP" );
	   }
	   catch (e1)
	   {
	    xhr2 = null;
	   }
	     }
	}
	
	return xhr2;
}