function altProps(){
	this.w3c=(document.getElementById)?true:false;
	this.ns4=(document.layers)?true:false;
	this.ie4=(document.all && !this.w3c)?true:false;
	this.ie5=(document.all && this.w3c)?true:false;
	this.ns6=(this.w3c && navigator.appName.indexOf("Netscape")>=0 )?true:false;
}

var AT=new altProps();

function Cacher(id)
{
	AT.id=(AT.ns4)?document.layers[id]:(AT.ie4)?document.all[id]:(AT.w3c)?document.getElementById(id):null;
	if(AT.ns4 && AT.id) {AT.id.visibility="hide";}
	else if(AT.id){
		AT.id.style.display="none";
		AT.id.style.visibility="hidden";		
	}	
}
function Afficher(id)
{
	AT.id=(AT.ns4)?document.layers[id]:(AT.ie4)?document.all[id]:(AT.w3c)?document.getElementById(id):null;
	if(AT.ns4 && AT.id)
		AT.id.visibility="show";
	else if(AT.id){
		AT.id.style.visibility="visible";
		AT.id.style.display="block";		
	}	
}
function getXmlHttpRequest(){
	var xhr;
	if (window.XMLHttpRequest)
		xhr = new XMLHttpRequest();
	else 
	if (window.ActiveXObject)
	{
		xhr = new ActiveXObject("Microsoft.XMLHTTP"); 
	}
	return xhr;
}