php - Modify regex in a script that highlights certain words in a text by adding span classes to them -

i working on code highlights words, using regex.

here is:

function addregex($word){         return "/\b(\w+)?".$word."(\w+)?\b/i";     }     function highlight($word){         return "<span class=\"highlighted\">".$word[0]."</span>";     }     function customhighlights($searchstring,$tohighlight){         $searchfor = array_map('addregex',$tohighlight);         $result = preg_replace_callback($searchfor,'highlight',$searchstring);         return $result;     } 

lets use function customhighlights searc word "car" in text:

using boundary - \b - method, script searches word car in text.

in regex, have added (\w+)? in front , after word, script match words contain "car" - cars, sportcars, etc...

the problem is, messes inner html, example:

this great car. click here <a href="http://cars.com">more</a> 

the script match word car in url of link above, adding span classes , messing html.

how modify regex , avoid this?

use regular expression searches word after last > or beginning of text, part between , word may not contain tag start <.

see codepad

code

<?php $str = 'this great car. click here <a href="http://cars.com">more cars</a>'; $word = 'car'; $exp = "/((^|>)[^<]*)(\b(\w+)?".$word."(\w+)?\b)/i"; $repl = "\\1<span class=\"highlighted\">\\3</span>"; var_dump(preg_replace($exp, $repl, $str)); ?> 

output

string(141) "this great <span class="highlighted">car</span>. click here <a href="http://cars.com">more <span class="highlighted">cars</span></a>"