I don't think you need a cookie. Instead of printing out a page from the CGI script, re-direct the user to a new page using an HTTP redirect.

open FH, ">>report_sum.txt" 
  or die "Cant open report_sum.txt Reason: $+!"; 
my $writestr="..."
print FH $writestr, "\n";    
close FH;

print redirect("http://mysite.com/thankyou.html");
[download]

NB: Make sure you don't print out anything else (including other HTTP headers) before the redirect.

</ajdelore>

Hi...
Thanks for your "redirect" script. It was something new, though I remember using it some years back. I have a question: Suppose I'm entering the details and submitting a form, the thankyou.html would get created, and would contain either the message "entry successful" or "fields invalid" and would display in the browser (lets say it shows me "fields invalid"). Suppose someone else did the same thing at the same time, and he/she entered all the fields successfully, then the thankyou.html would show "entry successful". What will happen if I refresh that page? It would also show me "entry successful" right?

I also thought of appending the thankyou.html with a timestamp, but that would lead to lot of such files getting created....
Any alternatives?
Thanks for your time.

Did you ever notice that when you blow in a dog's face, it gets mad at you but when you take him on a car ride,he sticks his head out the window and likes it?

#!/usr/bin/perl -w

print "Content-type: text/html\n\n";

use CGI;
$q = new CGI;

    ($sec,$min,$hr,$mday,$mon,$yr,$wkday,$yrday,$isdst) = localtime();
    $end = $min + 20;
    if ($end > 59) { $end - 60; }
    
print "Set-Cookie: endtime = $end\n";  #set the cookie

print "Minutes to end: $min to $end\n";

#some significant pause

$cookie = $q->cookie( "endtime" );  #get the cookie

print "$cookie\n";
[download]

I've got a form-->CGI scenario; let there be no re-entry of the same data.

There are a number of things to consider.

* What defines an invalid resubmission? Never twice by the same user? Never twice by the same machine/browser? (cookies come into play here) Never twice within 2 seconds /2 minutes / 2 hours? Perhaps one of the submitted fields can't be a duplicate?

Any of the above ideas are the basis for a code-based solution for distinguishing valid submisssions.

* If you do end up having the CGI set a cookie to indicate that this browser has submitted this form you'll run into a number of limitations. Cookies can be deleted due to space considerations. Your cookie won't be set prior to a user being able to click the submit button again (and again, and again).

One idea to help prevent users from clicking a submit button multiple times is to have a javascript function hide the submit button and message the user (Processing...) after the first submission. Your CGI would continue to work as needed.

A working example to put in your HTML:

you can use this Javascript and this code snippet below, using the onsubmit attribute of the form tag.

<script language="JavaScript">
<!--
function submitForm() {
    document.getElementById('submit').value = "Please Wait...";
    document.getElementById('submit').disabled = "disabled";
    return true;
}
//-->
</script>

<form method="post" action="login.asp" onsubmit="submitForm();">
    <input type="text" id="price" name="price"><br>
    ...
    <input id="submit" name="submit" type="submit" value="Send data">
</form>
[download]

Monks:
Please don't flame me for not addressing this in perl. I'm not aware of any client-side perl and this particular problem needs to be addressed on the client-side.

Cheers

-------------------------------------
Nothing is too wonderful to be true
-- Michael Faraday