a vanilla javascript approach to running scripts when jquery is loaded in based on a custom event

jquery-load-throw-catch.js

<script>
//PRE (jquery usecase only)
//load jquery library, inline or externally using defer or aysnc  
console.log('jQuery321 Ready! - version: ' + jQuery321().jquery)
$j = jQuery321.noConflict(); //map to new variable (extensible)


//THROW (include this after above in jquery file)
var myElement = document.querySelector('body');
var event = document.createEvent('Event');
event.initEvent('jq-rdy', true, true); //can bubble, and is cancellable
myElement.dispatchEvent(event);


//CATCH (use this wherever you want to do things after jquery is ready, without having to poll for it
document.querySelector('body').addEventListener('jq-rdy', function() {
  // TODO event handler logic
  console.log("caught something");
  console.log($.fn.jquery); //this will let you know if a different version of jquery is being loaded and mapped to $
  console.log($j.fn.jquery) //this is the jquery loaded from above
});
</script>