function ouvrir(mypage,myname,w,h)
{
var LeftPosition = (screen.width-w)/2;
var TopPosition = (screen.height-h)/2;
var settings = 'height='+h+',width='+w+',top='+TopPosition+',left='+LeftPosition+', scrollbars=no,resizable=yes';
PopUp = window.open(mypage,myname,settings);
PopUp.focus(); 
}