<script TYPE="text/javascript" LANGUAGE="JavaScript">
function fill_in_screensize() {
  document.forms['main_form'].width.value=screen.width;
  document.forms['main_form'].height.value=screen.height;
  return true;
}
</script>
....
....
<form name=main_form>
<input type=hidden name=width>
<input type=hidden name=height>
<input type=submit onClick='fill_in_screensize();'>
</form>
[download]

You have to know that unless the browser sends you this information somehow in the header, you can't directly retrieve it from your perl script that is ran Server-Side so I think your only bet is, besides asking the visitor for his screen resolution, to try and read it from JavaScript and do a window.location.href="http://someserver/perlscript.pl?width=" + screen.width + "&height=" + screen.height; in your JavaScript or something like that.

Just be sure that you have a default for people who do not have JavaScript turned on, so you do not alienate them from the site.

I hope this helps.

You have to know that unless the browser sends you this information somehow in the header, you can't directly retrieve it from your perl

Yeah, I didn't expect there would be. I thought perhaps there may be some undocumented ENV variable that I might not be aware of that CGI could grab -- but I doubted it.

I'm not looking to redirect users (at this point at least) so I'm not concerned beyond gathering this data. The site is designed to be fully functional from Netscape/Opera/MSIE 3x and greater, Mozilla and WebTV. I'm planning to enhance the "higher-end" functionality and display of the site however and rather than alienate lower-end visitors by introducing code that destroys their ability to use the site or limiting higher-end visitors from a full experience by catering to the lowest common denomenator, I am going to create a version geared at 800x600 or 1024x768 and higher and another for 800x600 or 640x480 and lower (largely plain text, tables and some images).

As far as asking visitors... I deal with thousands of visitors a week who often have a difficult time entering the correct email address and wonder where their registration confirmation went -- or worse -- think they always have to prepend their email addresses with 'www.'. Getting a screenre solution from some of them would be like trying to get a definition of quantum theory from Ted Nugent. :)

I didn't know thta I could simply refer to the Javascript vars outside of the SCRIPT tags without problems. That makes it much simpler!

I didn't know thta I could simply refer to the Javascript vars outside of the SCRIPT tags without problems

hold on a minute.. that line of code in my reply is a javascript code... you cannot use it outside script tags.. it just tells your browser to redirect to a specific address, which you construct based on the screen resolution you get..

---

He who asks will be a fool for five minutes, but he who doesn't ask will remain a fool for life.

Chady | http://chady.net/

would be like trying to get a definition of quantum theory from Ted Nugent.

Actually, from what I understand, the ol' WangoTango guy is pretty smart. Now, getting quantum theory from Britney Spears, on the other hand...

-- Randal L. Schwartz, Perl hacker
Be sure to read my standard disclaimer if this is a reply.

[HTML building some tables and the top-of-page navigation]

<SCRIPT TYPE="text/javascript" LANGUAGE="JavaScript">
function fill_in_screensize() {
     document.forms['login_form'].screen_width.value=screen.width;
     document.forms['login_form'].screen_height.value=screen.height;
     return true;
}
</SCRIPT>

<FORM name=login_form ACTION=[ACTION] METHOD=[METHOD]
<input type=hidden name=screen_width>
<input type=hidden name=screen_height>
[input fields for username and password]
<input type=submit value="submit" onClick='fill_in_screensize();'>
</FORM>
[download]

There is no way to know screen size, except using javascript. So the solution is to elegantly pass the value of the Javascript screen.width to a hidden form <input> that can be submitted to Perl.

FYI, this topic has been discussed on mod_perl mailing list at the end of March 2002.