javascript if 语句

<html>
   <body>

      <script type = "text/javascript">
         <!--
            var age = 20;

            if( age > 18 ) {
               document.write("<b>Qualifies for driving</b>");
            }
         //-->
      </script>

      <p>Set the variable to different value and then try...</p>
   </body>
</html>