function openDown(id)  
 { 
var window_width = 600;
var window_height = 450; 
var window_top = (screen.height-window_height)/2; 
var window_left = (screen.width-window_width)/2; 
newWindow=window.open("downDetails.aspx?downId="+id ,"","height=" +window_height+" ,width="+window_width+",left="+window_left+" ,top="+window_top+",resizable=no,scrollbars=yes,status=no,toolbar=no,menubar=no,location=no")
newWindow.focus();
}