accessing javascript variables within psp code

Bruno Desthuilliers bruno.42.desthuilliers at
Wed Jul 18 09:40:10 CEST 2007

BAnderton a écrit :
> Hello all,
> Question:  Is there any way to access a javascript variable from
> within psp code?

Short answer : no (or at least: not directly). And it has nothing to do 
with PSP.

Long answer: this has to do with the http protocol. Things go like this:

1/ the client (usually the browser) send a request (via typing an url in 
the address bar, clicking a link, posting a form...)

2/ the server process the request (this is where your psp - or any other 
server-side - code is executed) and send back a response (in your case, 
what has been generated by the psp code).

3/ the client do something (usually: display) the response. This is 
where Javascript - if any, and if supported by the client - is executed.

 From the server's POV, once the response is sent, the transaction is 

The only way to have client-side javascript communicate with the server 
is via the XmlHttpRequest object (IOW : ajax). This allow javascript 
code to send a request to a server without reloading the whole page.

> FYI, I've already found a workaround for the above example (by placing
> a "get" variable in the URL, reloading the page, and having psp check
> for the existence of that variable before proceeding with deleting the
> appropriate file) 

Beware, GET request should *not* have such side-effects on the server. A 
GET request is meant - as the name implies - to get data from the 
server. Use a POST request instead.

If you're going to do web development, reading the http RFC might be 

> but I'd still like this general capability for
> future projects.  

Then you have to learn how to use XmlHttpRequest.

> I've searched several forums, websites, etc. and
> the
> answer has aluded me for two days now.  I'm new to apache, mod_python,
> and javascript, so this may be ridiculously simple.
> Since this is my first post on google groups,

Small correction : you're not posting "on" google groups, you're posting 
on usenet *from* google groups. Most people prefer to access usenet via 
a newsreader.

> I'd also appreciate any
> helpful suggestions on how to best go about getting answers quickly

And remember that usenet is definitively not an help desk. No one get 
paid for answering your questions.


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