function OpenWinCenter( url, width, height, win_name )
{
     var iLeft = (screen.width  - width) / 2 ;
     var iTop  = (screen.height - height) / 2 ;

     var sOptions = "toolbar=no,status=no,resizable=yes,dependent=yes" ;
     sOptions += ",width=" + width ;
     sOptions += ",height=" + height ;
     sOptions += ",left=" + iLeft ;
     sOptions += ",top=" + iTop ;

     var oWindow = window.open( url, win_name, sOptions ) ;
}