Hi there. I am using preg_replace to add a link to keywords if they are found within a long HTML string. I don't want to add a link if the keyword is found within h1 tags or strong tags.

The below regex nearly works and basically says (I think): If the keyword is not immediately wrapped by either a h1 tag or a strong tag then replace with the keyword that was matched, as a bolded link to google.

$result = preg_replace('%(?!<h1>)(?!<strong>)\b(bobs widgets)\b(?!<\/strong>)(?!<\/h1>)%i','<a href="http://www.google.com"><strong>$1</strong></a>', $result, -1);

(the reason I don't want to match if in strong tags is because I am recursing through a lot of keywords so don't want to link an already linked keyword on subsequent passes)

the above works fine and won't match:

<h1>bobs widgets</h1>

It will however match the keyword in the following text, because the h1 tag isn't immediately either side of the keyword:

<h1>Here are bobs widgets for sale</h1>

I need to make the spaces either side optional and have tried adding \s* but that doesn't get me anywhere. I'd be very grateful for a push in the right direction here.