function hover_barre(e){
	if(window.event){
		var cible = window.event.srcElement;
	}else{
		var cible = e.target;
	}
	if(cible.className == "button"){
		cible.style.background = "url(Images/boutton/barre_button_on.png)";
	}
}
function down_barre(e){
	if(window.event){
		var cible = window.event.srcElement;
	}else{
		var cible = e.target;
	}
	if(cible.className == "button"){
		cible.style.background = "url(Images/boutton/barre_button_off.png)";
	}
}




function ecouteur(e){
	var barre_bas = document.getElementById('barre_bas');
	addEvent(barre_bas,'mouseover',hover_barre,false);
	addEvent(barre_bas,'mouseout',down_barre,false);
}

function addEvent(elm,evType,fn,useCapture){
	if(elm.addEventlistener){
		elm.addEventlistener(evType, fn, useCapture);
		return true
	}else if(elm.attachEvent){
		var r = elm.attachEvent('on' + evType, fn);
		return r;
	}else{
		elm['on' + evType] = fn;	
	}
}
addEvent(window,'load',ecouteur,false);