How to test HTML forms using simple remotely-accessible scripts

This document describes briefly some simple server-side scripts for testing HTML forms. Essentially, the scripts just echo back the data they receive.

This can be useful

• when you just want to get an idea of how data is passed to a server-side script from HTML forms
• when you have problems with your form and you wish to find out whether the problem is in the script or somewhere else; usually this is the first step in debugging, trying to isolate the problem by checking whether the script gets the data correctly
• when testing browsers--notice that there are some browser-dependent features in sending data from forms.

The scripts mentioned here work both for METHOD="GET" and for METHOD="POST".

My simple sendback script

My simple sendback script (written in Perl using the CGI.pm library) echoes the data it gets, with field names in one column and and field values in another column, in monospaced font. However, the data is decoded into plain text.

The script can handle forms with INPUT TYPE="FILE" fields (i.e. forms with ENCTYPE="multipart/form-data") too.

To use the script, simply take your FORM element and change the ACTION attribute to
ACTION="https://jkorpela.fi/cgi-bin/echo.cgi"

Example:

<FORM ACTION="https://jkorpela.fi/cgi-bin/echo.cgi"
METHOD="POST">
<P>
Type something:<BR>
<TEXTAREA ROWS=5 COLS=72 NAME=Comments>
This is
some text
in several lines.
</TEXTAREA>
<p>
<INPUT TYPE="checkbox" NAME="box" VALUE="yes">Check me!
<P>
<INPUT TYPE="HIDDEN" NAME="hidden field" VALUE="something">
<INPUT TYPE="SUBMIT" VALUE="Send">
</FORM>

Try it:

In some cases, you might wish to use an even simpler script, namely one that just echoes back the "raw" data as plain text, assuming it has been sent using the "post" method:

print "Content-Type: text/plain; charset=iso-8859-1\n\n";
print "Echoing raw form data:\n";
print;
while(<>) {
    print; }

(The script is at https://jkorpela.fi/cgi-bin/echoraw.cgi. The code prepends the text Echoing raw form data: and an empty line, so that you can distinguish between server malfunction and lack of data). This might be useful if you suspect that your browser cannot send data properly encoded or that the library routine that your script uses cannot decode it right.