if ((navigator.appName).indexOf("Microsoft")!=-1) {
  document.write('<link rel="stylesheet" href="http://www.wallersmithpalmer.com/test/ssi/wsp.css" type="text/css">');
}
else {
  document.write('<link rel="stylesheet" href="http://www.wallersmithpalmer.com/test/ssi/moz.css" type="text/css">');
}