function popup(url, name, _w, _h, _options)
{

if (!_options) _options="toolbar=0,location=0,menubar=0,scrollbars=0,dependent=yes,alwaysRaised=1,directories=0,status=false,resizable=1";

_left=(screen.width-_w)/2;
_top=(screen.height-_h)/2;

options="width="+_w+",height="+_h+",left="+_left+",top="+_top+","+_options;

w=window.open(url, name, options);
w.opener=self;
w.focus();

return w;
}