//<a href="javascript:popupcentree('screens.cfm?num=29',1024,640,'toolbar=no, directories=no, resizable=yes, scrollbars=no, status=no')"> 
function popupcentree(page,largeur,hauteur,options)
{
	if(options=="auto")
		options="toolbar=no, directories=no, resizable=yes, scrollbars=yes, status=no";
	
	var top=(screen.height-hauteur)/2;
	var left=(screen.width-largeur)/2;
	window.open(page,"","top="+top+",left="+left+",width="+largeur+",height="+hauteur+","+options);
}