var detected   = false ;
var useragent  = navigator.userAgent.toLowerCase() ;
var browserver = parseInt(navigator.appVersion) ;
var is_nav  = (useragent.indexOf('mozilla')!=-1) ;
var is_ie   = (useragent.indexOf("msie") != -1) ;

   if( is_ie )
   {
        if (browserver >= 4)
        {
           detected = true ;
        }
   }
   else if ( is_nav )
   {
        if (browserver >= 3)
        {
           detected = true ;
        }
   }
 if (detected == false)
   {
      location.href = "other.html";
   }