function openwin (url, w, h) {
    w += 40;	w = w < 250 ? 250 : w;	w = w > screen.availWidth - 50 ? screen.availWidth - 50 : w;
    h += 40;	h = h < 250 ? 250 : h;	h = h > screen.availHeight - 50 ? screen.availHeight - 50 : h;
//    w = 500;
//    h = 540;
    
    x = (screen.availWidth ? screen.availWidth : screen.width)/2 - w/2;		x = x > 0 ? x : 0;
    y = (screen.availHeight ? screen.availHeight : screen.height)/2 - h/2;	y = y > 0 ? y : 0;
    wd = window.open (url, '_blank', 'width='+w+'px,height='+h+'px,top='+y+'px,left='+x+'px,resizable=yes,scrollbars=yes');
    wd.focus ();
}