Question

I’ve developed a website (internal website behind a firewall) that uses a Java applet. If Java is not installed on the client, then it will fall back to other solutions.

The issue I now have is that at least IE9 pops-up a dialog saying that my webpage uses Java and how to install this. I’m already taking care of this on my webpage, so can I use some Meta tag or other to stop IE9 from ruining the user experience?

Users will think my webpage can’t be run without Java when this pop-up is shown!

HTML

<applet 
    id="tinyApplet" 
    width="0" 
    height="0" 
    codebase="/applet" 
    archive="se.lu.ldc.tiny.jar" 
    code="se.lu.ldc.tiny.applet.Tiny"> 
Some HTML text 
</applet> 

Answer 1

Have JS check that Java is installed before ever writing the applet element. E.G.

When you type..

alert(java.lang.System.getProperty("java.version"));

In the FF JS console input line, you might see something like:

[02:55:46.025] alert(java.lang.System.getProperty("java.version"));
[02:55:46.027] ReferenceError: java is not defined

..if Java is not installed. If it is not installed, use the alternate content/strategy.

If the call to getProperty(String) returns a non null value, then Java is installed (and java.version is a property defined in that JRE).