function popVR() {
if (document.all)
var xMax = screen.width, yMax = screen.height;
else
if (document.layers)
var xMax = window.outerWidth, yMax = window.outerHeight;
else
var xMax = 640, yMax = 480;
var xOffset = (xMax - 420)/2, yOffset = (yMax - 315)/2;
popup = window.open('/visite/entree.html','Visite360','width=420,height=315,screenX='+xOffset+',screenY='+yOffset+',top='+yOffset+',left='+xOffset+'');
}