jquery integration issue when attempted to execute on load It may just my limited js experience but until recently I had some js attached to the drupal context on one of my sites to produce some small animation/style effects that took the form:

$(window).on("load",function() {
    //do something
})


This worked great until recently then suddenly stopped working with no errors or messages. Eventually I got it working by changing the above to:

$(document).ready(function() {
    //do something
})


Did something change in core or jquery that caused this? Why would there be no errors? I use the first $(window).on() successfully on at least two other sites but have not been able to figure out why it stopped working on this one. 

Some of the js I wish to run relies on the entire page being fully loaded so I really would rather use $(window).on()- which I believe triggers later.

I am using the latest release version of drupal 8
As @Kevin mentioned 


  Drupal 8.4 introduced jQuery 3.x


And according to jQuery Core 3.0 Upgrade Guide  the "ready" event has been removed.

What you should do is to implement your functional code in Drupal.behaviours. This would have the similar effect as $(document).ready() but with more benefits.

(function ($, Drupal) {

  Drupal.behaviors.myHandler = {
    attach: function (context, settings) {
      // do something
    }
  };

})(jQuery, Drupal);