replace all “foo” between two HTML tags using REGEX (PHP code)

Question

I want a regex code , to replace all \"foo\" strings to \"bar\" , between the html tags pre>< /pre>

here is an example :

< html>
< p>          


        

Answer 1

$string = '< html>
< p> blah blah blah foo try foo< /p>
< pre> foo try foo word foofoo < /pre>
< /html>';
$string = preg_replace('/foo(?=(?:.(?!< pre>))*< \/pre>)/Um', 'boo', $string);
echo $string;