function popup(mypage, myname, w, h, scroll) {

//popup('pagina.php','frame',W,H);

var winl =( screen.width - w ) / 2;

var wint =( screen.height - h ) / 2;

winprops = 'height='+h+',width='+w+',top='+wint+',left='+winl+',scrollbars='+scroll+',resizable=no';

win = window.open(mypage, myname, winprops);

if( parseInt( navigator.appVersion ) >= 4 ) {

win.window.focus();

}

}