The JWS Portal Page

The portal page (shown in Figure B-9) contains a mix of JavaScript and VBScript, which attempts to detect if JWS is present on the client machine. If it isn't, then the user will be given the option of downloading a JRE. The task is considerably complicated by the many variations between browsers, operating systems, and platforms. Example B-4 is a simplified version of the page.

Example B-4. Simple version of JNLP portal page

    <HTML>
    <HEAD><TITLE>Java Web Start Portal</TITLE>
    <script language="JavaScript" type="text/javascript">
   
      // check in various ways if JWS is installed;
      // decide if the browser is IE on Windows
   
      function insertLink(url, name) {...}
      // add a link to the named URL if JWS is present
   
      function installInfo() {...}
      // report whether JWS has been found
   
      function nativeReport() {...}
      // warn about the use of Windows DLLs by BugRunner and Checkers3D</script>
   
    <script language="VBScript">
      // check for various JWS objects in the Windows registry
    </script>
   
    </HEAD>
    <BODY><H1>Java Web Start Portal</H1>
   
    <script language="JavaScript" type="text/javascript">
      installInfo();
      nativeReport();
    </script>
   
    <h2>Installation Links</h2>
    <P><ul>
      <li><script language="JavaScript" type="text/javascript">
        insertLink("time.jnlp", "Official US Time");
      </script>
   
      <li><script language="JavaScript" type="text/javascript">
        insertLink("BugRunner/BugRunner.jnlp", "BugRunner");
      </script>
   
      <li><script language="JavaScript" type="text/javascript">
        insertLink("Checkers3D/Checkers3D.jnlp", ...

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