<!-- This example is from the book _JavaScript: The Definitive Guide_.     -->
<!-- Written by David Flanagan.  Copyright (c) 1996 O'Reilly & Associates. -->
<!-- This example is provided WITHOUT WARRANTY either expressed or implied.-->
<!-- You may study, use, modify, and distribute it for any purpose.        -->

<!-- Set a variable to determine what version of JavaScript we support -->
<!-- This technique can be extended to any number of language versions -->
<SCRIPT LANGUAGE="JavaScript"> <!-- 
  _version = 10; // --> </SCRIPT>
<SCRIPT LANGUAGE="JavaScript1.1"> <!-- 
  _version = 11; // --> </SCRIPT>
<SCRIPT LANGUAGE="JavaScript1.2"> <!-- 
  _version = 12; // --> </SCRIPT>

<!-- If the version is not high enough, display a message -->
<!-- This version of the message appears for JavaScript 1.0 browsers -->
<SCRIPT LANGUAGE="JavaScript"> <!--
  if (_version < 11) {
    document.write('<HR><H1>This Page Requires JavaScript 1.1</H1>');
    document.write('Your JavaScript 1.0 browser cannot run this page.<HR>');
  }
// --> </SCRIPT>

<SCRIPT LANGUAGE="JavaScript1.1">
<!-- This version of the message will appear on non-JavaScript browsers -->
<!-- --> <HR><H1>This Page Requires JavaScript 1.1</H1>
<!-- --> Your non-JavaScript browser cannot run this page.<HR>
<!--  Start hiding the actual program code
        .
        .  // The actual JavaScript 1.1 code goes here.
        .
// Done hiding -->
</SCRIPT>
