Can I use a MutationObserver to listen for changes on computed styles?

Question

Can I use a MutationObserver to listen for changes on computed styles? I have a div which width is 100% and I\'d like to know when its computed width changes, but so far no

Answer 1

Support for observing style changes is in discussion. For now you could leverage transitions. The idea is to add a css transition for the width (or whatever) to the element. The transition should have a duration of almost zero, so you won't notice it.

After a transition has finished a transitionend event is fired. Add a listener for that event. Now whenever the width changes, the transition will start, immediately finish and the event will fire. Which means your listener will be called.

#myDiv {
  ...
  transition: width 0.01s;
}

$("#myDiv").on("transitionend", function () { ... } );

Supported by IE10+