As others have pointed out, chomp is not going to do what you want. The reason all elements of each array are being printed out is that the return from chomp will either be 0 if no line terminator was present at the end of the string, or 1 if there was and it was chomped away. In your arrays there are no terminators so the result of each chomp is zero, the if stringifies the two zeros and compares them resulting in equality true and the print statement is executed.

Perhaps I'm misunderstanding your question (or not reading your data correctly) but it appears to me that once you correct the chomp issue you will never see any output because there are no common elements. Could it be that the first element in @array1 has a typo and should be "the_form_below" rather than "the_for_below"?

Cheers,

JohnGG

Update: s/equality/true/ to make meaning clearer.

Update 2: Obviously, I can't read. There is an "and_press" string in each array. Correcting the assumed typo in @array1 and running this code

use strict;
use warnings;

my @array1 = (
   q{ the_form_below},
   q{this_job},
   q{complete},
   q{ and_press},
   );

my @array2 = (
   q{and_press},
   q{ online_Please},
   q{the_form_below },
   q{submit_will_only},
   );

for my $idx1 ( 0 .. $#array1 )
{
    for my $idx2 ( 0 .. $#array2 )
    {
        if( cleanUp( $array1[ $idx1 ] ) eq cleanUp( $array2[ $idx2 ] )
+ )
    {
        print
           qq{\$array1[ $idx1 ]: >$array1[ $idx1 ]<\n},
           qq{Equivalent to\n},
           qq{\$array2[ $idx2 ]: >$array2[ $idx2 ]<\n},
           q{=} x 40, qq{\n};
    }
    }
}

sub cleanUp
{
    my $str = shift;
    $str    =~ s{^\s+}{};
    $str    =~ s{\s+$}{};
    return $str;
}
[download]

gives the following output.

$array1[ 0 ]: > the_form_below<
Equivalent to
$array2[ 2 ]: >the_form_below <
========================================
$array1[ 3 ]: > and_press<
Equivalent to
$array2[ 0 ]: >and_press<
========================================
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$array1[$k] =~ s/^\s+//;
$array1[$k] =~ s/\s+$//;
$array2[$l] =~ s/^\s+//;
$array2[$l] =~ s/\s+$//;
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You would receive more specific help if you posted complete, running code that we could reproduce, along with your exact output and your exact desired output.

$array1[$k] =~ s/^\s+//;
$array1[$k] =~ s/\s+$//;
$array2[$l] =~ s/^\s+//;
$array2[$l] =~ s/\s+$//;
[download]

Maybe preferably use a little helper routine (or even existing code from a module such as Text::Trim):

# modify value in place
sub trim {
    $_[0] =~ s/^\s+//;
    $_[0] =~ s/\s+$//;
}

trim($array1[$k]);
trim($array2[$l]);

# --- or ---

# return the trimmed value
sub trim {
    my $s = shift;
    $s =~ s/^\s+//;
    $s =~ s/\s+$//;
    return $s;
}

$array1[$k] = trim($array1[$k]);
$array2[$l] = trim($array2[$l]);
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This has the advantage of documenting what's going on (with no extra effort), and if you need to trim a third or fourth time, the code would eventually get more compact.  Also, should you ever want to modify the regex, you'll only have to do it one place, so you'll not risk suffering from the cut-n-paste syndrome (one characteristic of which is that it's not only tedious, but also easy to overlook one of the several supposed-to-be-identical code fragments scattered about, when making modifications).

Also, generally try to avoid the variable name $l. With many fonts, it's difficult to discern $l (dollar-ell) from $1 (dollar-one)...
</nitpick>

I tried with your code and i removed chomp as well while comparing. But still the output is not coming correctly. Infact, its able to compare the two strings it seems.

use List::Compare;
use Data::Dumper;
s/\A\s+|\s+\z//g for @array1, @array2;
my $lc = List::Compare->new(\@array1, \@array2);
my @i = $lc->get_intersection();
print Data::Dumper->Dump([\@i]);
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Can you use a Data::Compare-type module?

if(chomp($array1[$k]) eq chomp($array2[l]))
---------------------------------------^
print"\n$array1[$k],$array2[$l]";
----------------------------^
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