function popup(url,width,height,scrollbars)
{
    if (height =='')
		height=350;
	if (width =='')
		width=450;		
	hauteur = height;
	largeur = width;    
	
	if (scroll =='') scroll=1;
	
	Left=window.screen.width/2-width/2;
	Top=window.screen.height/2-height/2;
	
	open1 = window.open(url,'_blank','height='+hauteur+',width='+largeur+',left='+Left+', top='+Top+',toolbar=0,status=yes,location=0,directories=0,menubar=0,scrollbars='+scrollbars+',resizable=0');
	open1.focus();    
}