At first: Use$|=1as early as possible in your script (usually you have #!/usr/bin/perl, use someting; $|=1;) otherwise your progress won't be shown until your script is done.

Here is what I'm using:

#!/usr/bin/perl
$|=1;
print '<header>'; # placeholder for your whole HTML header block
print '<span id=Progress>Working...</span>';
print '<footer>'; # placeholder for the rest of your document until bu
+t without </body>
sleep 1; # Something is done here
print <<_EOT_;
<script language=JavaScript type=text/javascript><!--
document.getElementById('Progress').innerHTML='Still working...';
//--></script>
_EOT_
sleep 1; # Something is done here
print <<_EOT_;
<script language=JavaScript type=text/javascript><!--
document.getElementById('Progress').innerHTML='Sorry, still not finish
+ed...';
//--></script>
_EOT_
sleep 1; # Something is done here
print <<_EOT_;
<script language=JavaScript type=text/javascript><!--
document.getElementById('Progress').style.display='none';
//--></script>
_EOT_
print '</body></html>'; # Page finished
[download]

I learned that most people prefer this:

#!/usr/bin/perl
$|=1;
print '<header>'; # placeholder for your whole HTML header block
print '<img src=animated.gif id=Progress>';
print '<footer>'; # placeholder for the rest of your document until bu
+t without </body>
sleep 1; # Something is done here
sleep 1; # Something is done here
sleep 1; # Something is done here
print <<_EOT_;
<script language=JavaScript type=text/javascript><!--
document.getElementById('Progress').style.display='none';
//--></script>
_EOT_
print '</body></html>'; # Page finished
[download]

Once I had a customer waiting three hours for the result not knowing that his internet connection broke early after starting the job.

These solutions are not the best ones - they don't use any modules. But they're simple and work for me in a number of projects. You could also output your data & footer after finishing the processing. In this case, add a <br>\r\n behind the Progress-object to force flushing the buffer (\r\n), sending to the client and showing to the user (<br>).