A CodePen by first-developer. Compute window size on resizing - Code use to compute window size when the browser is resizing

script.js

var windowResize = function(fun){
  var oldresize = window.onresize;

  window.onresize = function(e) {
    if (typeof oldresize == 'function') oldresize(e);
    fun(e);
  }
};

var res = function (e) {
  console.log([e.srcElement.outerWidth, e.srcElement.outerHeight]);
};

windowResize(res);