How does the use of urlencode affect the functionality of the highlight function?

When using the `highlight` function in PHP to highlight specific words in a string, if the words contain special characters, the function may not work as expected. This is because the `highlight` function does not handle special characters well. To solve this issue, you can use the `urlencode` function to encode the words before passing them to the `highlight` function. This will ensure that special characters are properly handled and the `highlight` function works correctly.

$words = "special characters";
$encoded_words = urlencode($words);
$string = "This is a string with special characters.";
$highlighted_string = highlight($encoded_words, $string);
echo $highlighted_string;