Checkout the complete HTML, Copy and save it in HTML extension.
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.2.0/jquery.min.js"></script>
<script type="text/javascript">
 $( document ).ready(function() {
   $('select[name=country]').on("change", function(e){
      if($(this).val() == 'USA'){
          alert($(this).val());
          window.location.assign("http://www.w3schools.com")
      }
      //window.location.url="www.google.com";
   });
});
</script>
</head>
<body>
<Select name="country">
   <option value="India">India</option>
   <option value="USA">USA</option>
</Select>
</body>
</html>
Hope this helps.