Re: How to inform web site visitor that Sun Java is required?

Lew <lew@lewscanon.nospam>
Thu, 21 Jun 2007 12:25:32 -0400
Brcobrem wrote:

I am by no means an expert html coder, but I can do enough to get small
jobs done. That said, I have a number of relatively simple web sites
that I developed (with FrontPage 2003) that require Java to display
certain components correctly. Is there some html code that I can insert
that would check if the user has Sun Java installed, and if they do not,
provide some kind of visual indication (perhaps a pop-up box) as
how/where to get Sun Java?

Joshua Cranmer wrote:

There is no HTML you could write, but there is some JavaScript:

function checkSunJava() {
    if (java.lang.System.getProperty("java.vendor").indexOf("Sun") != 0)
        alert('This page requires Sun Java.');

Alternatively, if your requirement is merely that the person needs Java,
this should (untested) work:

<applet ...> <!-- Or object or whatever -->
This page requires Java to work properly.

Alternatively you could use Java Web Start (JWS) if your design admits of that.

It gives you very good control over what Java versions you might require of
the user, and how to prompt them for it.

Sun's advice parallels Joshua's regarding the use of Javascript, or even
VBScript. There seem to be ways to configure the JNLP to control the Java
versioning also.

There's a tip on
on how to automagically download a Java for the MS Windows user.

I don't know if JWS is going to suit your needs.



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