Question

Want to replace some words on the fly on my website.

$content = preg_replace('/\bWord\b/i', 'Replacement', $content);

That works so far. But now i want only change the the words which are inside
div id=”content”

How do i do that?

Answer 1

$dom = new DOMDocument();
$dom->loadHTML($html);

$x = new DOMXPath($dom);
$pattern = '/foo/';
foreach($x->query("//div[@id='content']//text()") as $text){
   preg_match_all($pattern,$text->wholeText,$occurances,PREG_OFFSET_CAPTURE);
   $occurances = array_reverse($occurances[0]);
   foreach($occurances as $occ){
       $text->replaceData($occ[1],strlen($occ[0]),'oof');
   }
   //alternative if you want to do it in one go:
   //$text->parentNode->replaceChild(new DOMText(preg_replace($pattern,'oof',$text->wholeText)),$text);
}
echo $dom->saveHTML();
//replaces all occurances of 'foo' with 'oof'
//if you don't really need a regex to match a word, you can limit the text-nodes 
//searched by altering the xpath to "//div[@id='content']//text()[contains(.,'searchword')]"