Deploying Applets in a Mixed-Browser Environment

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Trail: Deployment
Lesson: Applets

Deploying Applets in a Mixed-Browser Environment

You can deploy applets for users of both Internet Explorer and the Mozilla family of browsers in one of two ways:

Through pure HTML

Through JavaScript

Using Pure HTML

When using a pure HTML approach to deploy applets in a mixed-browser environment, note the following:

Internet Explorer

Recognizes the object tag

Ignores the contents of the comment tag

Mozilla browsers

Ignore an object tag with the classid attribute

Interpret the contents of the comment tag

Consider the following example code from an HTML page:
<object 
  classid="clsid:CAFEEFAC-0015-0000-0000-ABCDEFFEDCBA"
  <param name="code" value="Applet1.class">
    <comment>
      <embed code="Applet1.class"
        type="application/x-java-applet;jpi-version=1.5.0">
        <noembed>
          No Java Support.
        </noembed>
      </embed>
    </comment>
  </object>

Using JavaScript

Instead of using the pure HTML approach described above, you can use JavaScript to deploy applets in a mixed-browser environment.

Through JavaScript, you:

Detect the user's browser through the appName variable.

Use the document.write() method to write a tag based on the value of the appName variable:

If the browser name equals "Netscape", write the embed tag.

If the browser name equals "Microsoft Internet Explorer", write the object tag.

In the following example, the document.write() method outputs either an embed or object tag for each user “on the fly”:
<html>
<script language="Javascript">

  var _app = navigator.appName;

  if (_app == 'Netscape') {
    document.write('<embed code="Applet1.class"',
                   'width="200"',
                   'height="200"',
                   'type="application/x-java-applet;version=1.5.0">');
    }
  else if (_app == 'Microsoft Internet Explorer') {
    document.write('<OBJECT ',
                   'classid="clsid:8AD9C840-044E-11D1-B3E9-00805F499D93"',
                   'width="200"',
                   'height="200">',
                   '<PARAM name="code" value="Applet1.class">',
                   '</OBJECT>');
    }
  else {
    document.write('<p>Sorry, unsupported browser.</p>');
    }

</script>
</html>
You can use the HTML Converter tool to help with generating object and embed tags for mixed environments.

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