Global Variables and ClientSide Javascript

haricot · September 7th, 2005, 08:16 AM

Good Morning all,

(An ASP Beginners question):
Recently I learned about "application" and "session" variables defined in global.asa and now want to examine/use/update them from the client-side using javascript.

Following the examples in the Active Server Pages 3.0 book (Chap 8), I can at least show the value of the variables using vbscript **<%= Session("VisitorID")%>**, but so far have been unable to read them into a java defined variable, let alone change them! There must be away I am sure!

So in short.
. I want to examine a variable created in the global.asa file
. Change it (if necessary)
. All from Java (client-Side).

Would some kind soul put me out of my misery - It's really doing my head in :(!

Kind Regards,
Michael

Michael

ChrisScott · September 7th, 2005, 09:08 AM

Hi Michael,

Because application and session variables are server-side and your JavaScript runs client-side, you cannot directly access the variables from JavaScript.

You could populate javascript variables with the values from the server when you build your pages e.g.

Code:

var myVar = "<%=Session("mySessionVar")%>";

Another way would be to write the server-side variable values into form fields and then access them from there.

If you want to update the variables from client-side, you will have to collect the details of the update on the client and then send them back to the server to make the changes.

HTH,

Chris

haricot · September 7th, 2005, 09:40 AM

Thanks Chris for the speedy reply,

Although it is not the answer I wanted to hear! - Hardly your fault though :)

I really wanted to be able to adjust the session variables without reloading the page, (as the page in question calls another program that runs interactively).

If I could trouble you further...

Your initial suggestion: **var myVar="<%=Session("mySessionVar")%>";**
I build my pages using vbscript, so how do I include a java definition? (Yes, I really am a beginner!!)

As per the second suggestion, I guess I can hide an iframe with a hidden form in the page and have that refresh itself. I should be able to extract the session values from it and then modify them from my javascript then post the form back. Does that make sense? Are there security issues I should think about?

Thank you again,
Michael

ChrisScott · September 7th, 2005, 10:00 AM

Hey Michael,

Just to clarify, I was talking JavaScript and not Java.

If you want to write the values to JavaScript variables, just add the script to your html, something like...

Code:

<script language="JavaScript">
var myVar="<%=Session("mySessionVar")%>";
</script>

This will write the value into the script block before the page is sent to the browser.

Your idea about a hidden form would work, depending on your target audience, you could also consider M$ XmlHttp or Mozilla XMLHttpRequest objects, which allow a remote request direct from a script.

Cheers,

Chris
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