ns = (document.layers)? true:false;
ie = (document.all)? true:false;

 var browser=navigator.appName;
 var version=navigator.appVersion
 var ver1=version.substring(0,1)
 var ver2=version.lastIndexOf("MSIE")
 var ver3=version.substring(ver2+5,ver2+6)

 function itsNetscape() {
  document.write('<LINK REL=StyleSheet HREF="http://www.braslink.com.br/braslinkns.css" TYPE="text/css">')
 }
 function itsMsie() {
  if (browser == "Microsoft Internet Explorer")
  ieVersion()
 }
 function ieVersion(){
  if (ver1 >= 4)
   document.write('<LINK REL=StyleSheet HREF="http://www.braslink.com.br/braslink.css" TYPE="text/css">')
  if (ver3 == 3)
   document.write('<LINK REL=StyleSheet HREF="http://www.braslink.com.br/braslink.css" TYPE="text/css">')
 }
 if ((browser == "Netscape") && (ver1 >= 4)){
  itsNetscape()
 }
 else{
  itsMsie()
 }