Regex search and replace only within a section of HTML

There are cases where you might need to limit the multiple replacements that SiteSpect would do to a specific section of page source

Let's say you have a page that looks like:

.
.
.
<body>
<div>some content</div>
<img src="/path0">

<div id="contentWrapper">
<img src="/path1">
<img class="someclass" src="/path2">

</div>

<div id="new">Hello</div>

<img src="/path3">
<div>some content</div>

</body>
</html>

And you want to add a class to the images that are within the contentWrapper div. Regex can be used to limit the scope of search and replace by using look aheads - one negative and one positive.

Consider a search

<img(?!.*<div id="contentWrapper">)(?=.*<div id="new")

which effectively says match on the <img string while <div id="contentWrapper"> is not after and <div id="new" is after.

So the replace might be

<img class="lazy-load"

but it will be limited to the two img tags in the contentWrapper div