I have a simple bit of code below that I am using as a cgi script. When the code loads, you see the form as I intended. If you put a check in the Test Check Box and then click the submit button, you will then see the key/value pairs present in the form. That is all fine. Once the submit button is clicked, you will notice that the check box is then unchecked. Again, all is fine with that. However, when you click reload in your browser, the check box remains unchecked however the value of the checkbox variable remains the same (ON in this case). I am searching for a way to reload the page such that the value is empty, as it is when you first run it. In other words, when the check box clears, I wish for the variable to be cleared as well instead of maintaing it's value and being printed again on the screen.

Obviously this is just a test script, but it demonstrates a problem I am having in a larger script. That script has a counter that does addition when a check box is checked. If the check box is checked and the submit button is clicked it does the addition but it also does the same addition each time the reload button is checked.

How can I prevent this behavior?

See sample below. 
#!/usr/bin/perl
print "Content-type: text/html\n\n";
print "<form method='POST' action='/cgi-bin/demo.cgi'>\n";
print "Test Check Box <input type='checkbox' name='CheckBox' value='ON
+'></p>\n";
print "<input type='submit' value='Submit' name='Submit'><input type='
+Reset' value='Reset' name='B2'></p>\n";

&ParseForm;

foreach $key (sort keys(%formdata)) {
  print "KEY=$key<br>\n";
  print "VALUE=$formdata{$key}<br><br>\n";
}

sub ParseForm {
if ($ENV{'REQUEST_METHOD'} eq 'GET') {
      @pairs = split(/&/, $ENV{'QUERY_STRING'});
  } elsif ($ENV{'REQUEST_METHOD'} eq 'POST') {
      read (STDIN, $buffer, $ENV{'CONTENT_LENGTH'});
      @pairs = split(/&/, $buffer);
  } else {
      print "Content-type: text/html\n\n";
      print "<P>Use Post or Get";
  }
  foreach $pair (@pairs) {
      ($key, $value) = split (/=/, $pair);
      $key =~ tr/+/ /;
      $key =~ s/%([a-fA-F0-9] [a-fA-F0-9])/pack("C", hex($1))/eg;
      $value =~ tr/+/ /;
      $value =~ s/%([a-fA-F0-9] [a-fA-F0-9])/pack("C", hex($1))/eg;
      $value =~s/<!--(.|\n)*-->//g;
      if ($formdata{$key}) {
          $formdata{$key} .= ", $value";
      } else {
          $formdata{$key} = $value;
      }
  }
}

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In reply to HTML Form retaining values by Anonymous Monk

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