Find javascript that is changing DOM element

The accepted answer doesn't fully answer the question, because it doesn't help with page loads.

I solved this issue but putting a script block immediately following the element in question.

<script type="text/javascript"> debugger; </script>

I was then able to attach the dom motification break points. By right clicking the element and selecting "break on" -> "attribute modifications" in the developer tools as described in other answers.

Right click on DOM element > Break on > Attributes Modifications

Via #3 in https://elijahmanor.com/blog/7-chrome-tips-developers-designers-may-not-know