Check if any given script has loaded

script-loaded.js

var myScript = document.createElement('script'); 
myScript.src = 'http://code.jquery.com/jquery-2.1.4.min.js';
myScript.onload = function() { 
  console.log('jQuery loaded.');
};

document.body.appendChild(myScript);

This doesn't check if any script is loaded, it just loads a script...

Yeah, @DutchKevv is right, this loads the script. What it is doing though is executing that function when it is finished loading.

This one duplicates when 2 instances of the same file try to load, you might want to try https://gist.github.com/alecsgone/b19cc0f45a76b1fbda31ba58a865d4a6

I wish I could found a down-vote button