function ajax()
{
	var xhr	=	null	; 
	if (window.XMLHttpRequest)
	{
		xhr = new XMLHttpRequest()	;
	} 
	else if(window.ActiveXObject)
	{
	   try
	   {
			xhr = new ActiveXObject("Msxml2.XMLHTTP");
		}
		catch (e)
		{
			xhr = new ActiveXObject("Microsoft.XMLHTTP");
		}
	}
	else
	{
		alert("Votre navigateur peut poser certains probl\352mes de compatibilit\351...")	; 
		xhr = false																			;
	}
	return xhr;
}