Set style change event listener in Javascript

Question

My div looks something like this:

Answer 1

You can use MutationObserver

Then code example:

var observer = new MutationObserver(function(mutations) {
mutations.forEach(function(mutationRecord) {
    console.log('style changed!');
   });    
 });

 var target = document.getElementById('myId');
  observer.observe(target, { attributes : true, attributeFilter : ['style'] });

Note: this only works with inline styles(any changing of styles), not when the style changes as a consequence of class change or @media change This is a answer https://stackoverflow.com/a/20683311/3344953