Hi Senthil,

Pls. try the below.

@Data=<DATA>;
foreach $line(@Data)
{
    if ($line=~s#(<h([0-9]+)>(?:.+?))#$1#)
    {
        $curr=$2;
        $endtag='</table>';
        $line=~s#^(<h[0-9]+>)?(.+?$)#$1<tr><td>$2</td></tr>#;

        if ($prev=~m#^$#)
        {
            $line=~s#<h[0-9]+>#<table>#g;
        }
        elsif ($prev == $curr)
        {        
            $line=~s#<h[0-9]+>##;
        }
        elsif ($prev > $curr)
        {
            $x=$prev-$curr;
            for ($i=0; $i<$x; $i++)
            {
                $line="$endtag\n".$line;
            }
            $line=~s#<h[0-9]+>##;
        }
        $line=~s#<h[0-9]+>#<table>#g;
    }

    $prev=$curr;

    $Final.=$line;
}

$Final=$Final.'</table>';

print $Final;


__DATA__
<h1>Heading Level 1
<h2>Heading Level 2
<h2>Heading Level 2
<h2>Heading Level 2
<h3>Heading Level 3
<h3>Heading Level 3
<h2>Heading Level 2
<h1>Heading Level 1
[download]

Output:

<table><tr><td>Heading Level 1</td></tr>
<table><tr><td>Heading Level 2</td></tr>
<tr><td>Heading Level 2</td></tr>
<tr><td>Heading Level 2</td></tr>
<table><tr><td>Heading Level 3</td></tr>
<tr><td>Heading Level 3</td></tr>
</table>
<tr><td>Heading Level 2</td></tr>
</table>
<tr><td>Heading Level 1</td></tr>
</table>
[download]

Thanks,

Gopal.R.