function openwebsitecredits()
{
lmargin = (screen.width-500)/2
tmargin = (screen.height-375)/2
window.open('website_credits.htm','win','width=520,height=395,top='+tmargin+',left='+lmargin+',toolbar=false,location=false,status=false,menubar=false,scrollbars=yes,resizable=false');
}