if ( param ) {
} else {
}
sub start_handler {}
sub char_handler  {}

##</code><code>##

sub start_handler {
      my ($expat, $element, %attributes) =@_;
      if ($::flag==0 && $element eq "username") {
         $::flag=1;
      }

      if ($::flag==1 && $element eq "password") {
         $::flag=2;
      }
}

##</code><code>##

sub start_handler {
    my $element = $_[1];
    $::flag = 1 if $::flag == 0 && $element eq 'username';
    $::flag = 2 if $::flag == 1 && $element eq 'password';
}

##</code><code>##

sub char_handler {
    my ($expat, $text) =@_;
    if ($::flag==1 && $text eq (param("username"))) {
       $::flag=1;
    }

    if ($::flag==2 && $text eq (param("password"))) {
       my($un);
       $un=param("username");
       print redirect("http://www.domain.com/cgi-bin/xml_final/viewdb.pl?username=$un");
    }
    elsif ($::flag==2 && $text ne (param("password"))) {
       $::flag=0;

       print header;
       print start_html(-title => "Not so much correct with tha login" ,-style => {
          -src => "../..//xml_final/db.css"});
       print h1("incorrect password");
       print p({-align=>'CENTER'},a{-href=>"login.pl"},"Try Agian?");
       print end_html;
       #print a link back to login.pl
    }
}

##</code><code>##

    return unless $::flag;

##</code><code>##

    warn '$::flag must be 0, 1, or 2 only' if $::flag > 2 or $::flag < 0;

##</code><code>##

    my $text = $_[1];

##</code><code>##

    if ($::flag==1 && $text eq (param("username"))) {
       $::flag=1;
    }

##</code><code>##

    if       ( $::flag==2 && $text eq param('password') ) {
    } elsif  ( $::flag==2 && $text ne param('password') {
    }

##</code><code>##

    if ( $::flag==2 ) {
        if ( $text eq param('password') ) {
        } else {
        }
    }

##</code><code>##

    return unless $::flag == 2;
    if ( $text eq param('password') ) {
    } else {
    }

##</code><code>##

    if ( $text eq param('password') ) {
        print redirect( 'http://www.domain.com/cgi-bin/xml_final/viewdb.pl?username=' . param('username') );
    } else {
        print
            header,
            start_html(
                -title => 'Not so much correct with that login',
                -style => {-src => '../..//xml_final/db.css'} ),

                h1('Incorrect password'),
                p({-align => 'center'},
                    a({-href => 'login.pl'}, 'Try Agian?') ),
            end_html;
    }
    exit;   # no reason to continue processing if the browser is moving on

##</code><code>##

sub char_handler {
    return unless $::flag;

    my $text = $_[1];

    warn '$::flag must be 0, 1, or 2 only' if $::flag > 2;

    return unless $::flag == 2;

    if ( $text eq param('password') ) {
        print redirect('http://www.domain.com/cgi-bin/xml_final/viewdb.pl?username=' . param('username'));
    } else {
        $::flag = 0;
        print
            header,
            start_html(
                -title => 'Not so much correct with that login',
                -style => {
                    -src => '../..//xml_final/db.css'}),

                h1('Incorrect password'),
                p({-align => 'center'},
                    a({-href => 'login.pl'}, 'Try Agian?') ),
            end_html;
    }
    exit;
}

##</code><code>##

   my ($parser, $document, $users);
   local($::flag);
   $::flag=0;
   open(USERS, "../../xml_final/users/users.xml") ||
      die "Could not open users.xml $!";
   flock(USERS, LOCK_SH);

print header, start_html(-title => "Login" ,-style => {
      -src => "../../xml_final/db.css"}), title ("please login");
print start_html;

   $parser= new XML::Parser();
   $parser->setHandlers(
    Start => \&start_handler,
        Char  => \&char_handler
   );

   $document = $parser->parse (\*USERS);
   close (USERS);

##</code><code>##

$::flag = 0;
open USERS, '../../xml_final/users/users.xml' or die "Could not open users.xml: $!";
flock(USERS, LOCK_SH);
    my $parser = new XML::Parser();
    $parser->setHandlers(
        Start => \&start_handler,
        Char  => \&char_handler);

    my $document = $parser->parse(\*USERS);
close USERS;

##</code><code>##

unless ( param ) {
    print login_form();
    exit;
}

sub login_form {
    return
        header,
        start_html(
            -title => 'Login',
            -style => {
                -src => "../../xml_final/db.css"}),
            center(
                h1('Please login'),
                start_form,
                        'username:', textfield( -name => 'username'),
                        'password:', password_field( -name => 'password'),
                        submit('send'),
                        reset,
                end_form,
                a({ -href => 'newuser.pl'}, 'New User?') ),
        end_html;
}

##</code><code>##

#!/usr/bin/perl

use strict;
use warnings;
use CGI qw( :standard center);
use Fcntl qw( :flock );
use XML::Parser;

unless ( param ) {
    print login_form();
    exit;
}

$::flag = 0;
open USERS, '../../xml_final/users/users.xml' or die "Could not open users.xml: $!";
flock(USERS, LOCK_SH);
    my $parser = new XML::Parser();
    $parser->setHandlers(
        Start => \&start_handler,
        Char  => \&char_handler);

    my $document = $parser->parse(\*USERS);
close USERS;

sub login_form {
    return
        header,
        start_html(
            -title => 'Login',
            -style => {
                -src => "../../xml_final/db.css"}),
            center(
                h1('Please login'),
                start_form,
                        'username:', textfield( -name => 'username'),
                        'password:', password_field( -name => 'password'),
                        submit('send'),
                        reset,
                end_form,
                a({ -href => 'newuser.pl'}, 'New User?') ),
        end_html;
}

sub start_handler {
    my $element = $_[1];
    $::flag = 1 if $::flag == 0 && $element eq 'username';
    $::flag = 2 if $::flag == 1 && $element eq 'password';
}

sub char_handler {
    return unless $::flag;

    warn '$::flag must be 0, 1, or 2 only' if $::flag > 2 or $::flag < 0;

    return unless $::flag == 2;

    my $text = $_[1];
    if ( $text eq param('password') ) {
        print redirect('http://www.domain.com/cgi-bin/xml_final/viewdb.pl?username=' . param('username'));
    } else {
        print
            header,
            start_html(
                -title => 'Not so much correct with that login',
                -style => {
                    -src => '../..//xml_final/db.css'}),

                h1('Incorrect password'),
                p({-align => 'center'},
                    a({-href => 'login.pl'}, 'Try Agian?') ),
            end_html;
    }
    exit;
}