The script that is called when a user clicks the Submit button is Login.pl. This script will take the
values in the Username and Password box and validate that they match against the database. If a
match is found, the requested Web page will be generated; if not, the user will be asked to log in again.
Listing 21.4 is the complete listing of Login.pl.
Listing 21.4 Script for User Log In

#!/usr/local/bin/perl

&GetFormInput;

The intermediate variables below

#make your script more readable

but somewhat less efficient

#since they are not really necessary.

$Username = $field{'Username'} ;

$Password = $field{'Password'} ;

$message = "" ;

$found_err = "" ;

$errmsg = "

Field 'Username' must be filled in.

if ($Username eq "") {

$message = $message.$errmsg ;

$found_err = 1 ; }