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Website by Michael Horowitz 
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Website by Michael Horowitz
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Although most current web browsers are capable of running Java applets (programs), this support can be disabled. Below are some ways to tell if your browser is Java enabled.
The HTML test below should indicate if your browser currently supports Java.
| LIVE |
This web browser can run Java applets. |
A browser that supports Java displays: "This web browser can indeed run Java applets" and it should look like:
| sample |  |
A browser that does not support Java displays: "This web browser can NOT run Java applets" and should look like:
| sample |  |
How this works: Applets are included in a web page with the HTML APPLET tag.
Web browsers that do not support Java (either because they can not or because a
configuration option has been set to disable Java) are supposed to display text
inside the <APPLET> tag. The above test is coded using HTML that looks
like:
This
web browser can <applet ...>NOT</applet> run Java applets
If the applet can run, it displays the word "indeed" in blue. If it can not run, the web browser is supposed to display the word "NOT".
Note that Firefox 1.0 with Java and the Adblock extension wraps the display on two lines (seems to be a Firefox bug). Firefox 1.0 without Java and with no extensions, does not correctly display the word "NOT" (another bug). Instead it displays a green jigsaw puzzle piece.
You can manually enable or disable the use of Java by a web browser. This would, for instance,
let you run Java in one browser, but not in another. Or, it would let you keep Java installed
and disabled most of the time, and then just enable it when needed.
The instructions below
have been tested only in Windows 7 and XP using Java version 6 update 20.
>> In Firefox 3.6.10, do Tools -> Add-ons -> Plugins.
There are two Java entries: Java Deployment Toolkit and Java Platform.
If they are both enabled, Java should work.
If they are both disabled, Firefox will not run Java applets.
For more about Java and Firefox see
support.mozilla.com/en-US/kb/Java.
Firefox users can get more granular control over Java and other stuff with the
NoScript extension.
Firefox 3 used to offer a checkbox to enable Java under Tools ->
Options -> Content Panel, but at some time during the lifespan of Firefox v3, this
disappeared.
>> Chrome version 6 users can enter "about:plugins" in the address bar to enable and/or disable Java and other plugins. There is a single entry for Java identified as "Java 6". Personally, I make a bookmark for the about:plugins page.
>> In Internet Explorer 8 under Windows XP , do Tools -> Manage Add-ons -> Toolbars and Extensions (the default). There are two entries from Sun Microsystems, the Web Browser Applet Control (an Activex control) and Java(tm) Plug-In 2 SSV Helper (a Browser Helper Object). If they are both disabled, Java applets will not run. If they are both enabled, Java applets will run.
>> In Internet Explorer 8 under Windows 7, it's hopeless. Nothing prevents Java from running.
JavaScript is a programming language run by your web browser. If your browser supports JavaScript and this support is enabled, then we can use a JavaScript function to report on whether Java is enabled or not. This is what JavaScript reports about your browser:
This is done with a JavaScript command much like:
document.write("Is Java enabled? " + navigator.javaEnabled() );
Note: I've been told more than once that under Windows XP SP2 with IE6 that this test reports "True" even if Java is not installed. I haven't confirmed this myself. I did notice that on an XP system that just had Sun's Java un-installed (prior to installing a newer version), this reported "True" because it fell back to using Microsoft's Java. I've also been told that on Windows ME, IE 5.5 falsely reports Java as "true" when there is no Java instaled.
The NoScript extension for Firefox, originally designed to block JavaScript, can also block Java applets as well as Flash and Silverlight.
A reader of this page suggested this technique (thanks Ed) way back when. It seems, however, to be the least reliable method. In theorey, if Java is enabled it should say "I'm here" in between the arrows below.
This is done using the following JavaScript and Java commands:
<script> document.write(new
java.lang.String("I'm here")); </script>
This does not work with Chrome v6, where a browser that happily runs Java applets, does not admit to being here. It also does not work (I'm told) with IE v9 beta 1 under Windows 7 and with Firefox v4 beta under Windows 7 (as of Oct. 2010). It does work with Firefox 3.6.10 (at least under Windows XP).
In the old days, this did not work with Internet Explorer v6 under Windows 2000 (May 2005). It did work, however, with Firefox v1.0.4. (Windows 2000)
If Java is installed, but not enabled, Sun has instructions to Enable the JRE through your Web browser and to Enable the JRE through the "Java™ Plug-in Control Panel". Sun also has a Test Java Virtual Machine web page that did not work for me. See the Installing page for more on this.