function popup(url,windowname,features) 
{ 
width=500;
height=370;
width=(width)?width:screen.width/2; 
height=(height)?height:screen.height/2; 

var screenX = (screen.width/2 - width/2); 
var screenY = (screen.height/2 - height/2); 
var features= "width=" + width + ",height=" + height +",scrollbars=no,status=no"; 
features += ",screenX=" + screenX + ",left=" + screenX; 
features += ",screenY=" + screenY + ",top=" + screenY; 

var mywin=window.open(url, windowname, features); 
if (mywin) 
mywin.focus(); 
return mywin; 
} 

function popup_petit(url,windowname,features) 
{ 
width=250;
height=200;
width=(width)?width:screen.width/2; 
height=(height)?height:screen.height/2; 

var screenX = (screen.width/2 - width/2); 
var screenY = (screen.height/2 - height/2); 
var features= "width=" + width + ",height=" + height +",scrollbars=no,status=no"; 
features += ",screenX=" + screenX + ",left=" + screenX; 
features += ",screenY=" + screenY + ",top=" + screenY; 

var mywin=window.open(url, windowname, features); 
if (mywin) 
mywin.focus(); 
return mywin; 
}