function change_largeur() {
	var ccol = document.getElementById("conteneur");
	if (navigator.appName == "Microsoft Internet Explorer") {
		var cwinwidth=document.body.getAttribute('offsetWidth');
		var newcolwidth=cwinwidth - 30;
		ccol.style.setAttribute('width',newcolwidth);
	}
	else {
		var cwinwidth=window.innerWidth;
		var newcolwidth=cwinwidth - 30;
		ccol.style.width=newcolwidth+"px";
	}
}