Take a look at this example: https://jsfiddle.net/vxun2Lgg/2/

I've attached an "resize" event listener on container div. After opening up dev tools, and modifying the width of container, resize callback does not get called. What am I missing?

PS:
I am not interested in window resize event, only in container div.

var container = document.getElementsByClassName(container)[0];

container.addEventListener(resize, function() {

  console.log(resizing)

});

<div class=container></div>