Affiliate url rotator help

</head>
<title></title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<frameset rows="20,*" frameborder="0" border="0" framespacing="0">
<frame src="topnav52308.htm" name="top" marginheight=0 marginwidth=0 leftmargin=1>
<frame src="www.YOURDOMAIN.COM" name="main" marginheight=0 marginwidth=0 leftmargin=1>
</frameset>
<NOFRAMES>
</html>

<?php

$randomnum = rand(1,10);

switch ($randomnum)
{
case 1:
  echo "www.affiliatelink1.com";
  break;
case 2:
  echo "www.affiliatelink2.com";
  break;
case 3:
  echo "www.affiliatelink3.com";
  break;

  etc...
}
?>