function isWin()
{

  return (navigator.appVersion.indexOf("Win") != -1);
}

function isMac()
{

  return (navigator.appVersion.indexOf("Mac") != -1);
}

function isNav()
{

  return (navigator.appName == "Netscape");
}

function isIE()
{

  return (navigator.appName == "Microsoft Internet Explorer");
}

function isMSIE3Min()
{

  return (navigator.appVersion.indexOf("MSIE") != -1);
}