What are potential pitfalls when using regular expressions in PHP for highlighting search terms?

One potential pitfall when using regular expressions in PHP for highlighting search terms is that special characters in the search terms can break the regular expression pattern. To solve this issue, you can use the preg_quote() function to escape special characters in the search terms before using them in the regular expression pattern.

$search_term = $_GET['search_term'];
$escaped_search_term = preg_quote($search_term, '/');
$highlighted_text = preg_replace('/' . $escaped_search_term . '/i', '<span class="highlight">$0</span>', $text_to_highlight);
echo $highlighted_text;