tail -f /var/log/apache2/access_log

And you can watch what the webserver is receiving. Hardly effort, and often useful.

Not really

• assumes a shell
• assumes aforementioned changes to html file
• assumes aforementioned changes to cgi file
• requires a human to interpret raw URLs with his mind

If OP was able to do all this when you suggested it, then the OP wouldn't need help debugging this

Basically its bad advice.