function centre_popup(url,width,height,options)
{
var yer=(screen.height-height)/2;
var xer=(screen.width-width)/2;

	if (options=="fullscreen") {
	xer=0;
	yer=0;
	width=screen.availWidth-1;
	height=screen.availHeight-1;
	}
paramStr = "width=" + width + ",height=" + height + ",screenX=" + xer + ",screenY=" + yer + ",left=" + xer + ",top=" + yer + ",dependent=1,directories=0,location=0,menubar=0,resizable=yes,scrollbars=yes,toolbar=0";
fenetre_popup=window.open(url,"popup",paramStr);
fenetre_popup.focus();
}