I always think that parsing HTML with regexp's is bad and go for something like HTML::Parser or HTML::TreeBuilder everytime. This may or may not be an overkill for your situation.

use HTML::Parser;

my $keyword = quotemeta 'match';

sub highlight {
    my $text = shift;
    $text =~ s|\b($keyword)\b|<span style="background: #FFFFFF">$1</sp
+an>|g;
    return $text;
}

my $html = q{
    <p id="match"><b>this is html match this</b><u value="don't match 
+this">text html blah</u></p>
};

my $p = new HTML::Parser(api_version => 3, 
    handlers => {
        text=> [ sub { print highlight(shift) }, 'text'],
    default => [sub { print shift }, 'text'],
  });

$p->parse($html);
[download]

gav^

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.