script src=”./path/to/assets/js/script.js”>

(function () {
var randoms = Math.ceil(Math.random() * 1000000000);
var someJs = “./path/to/assets/js/script.js?r=” + randoms;

window.onload = function() {
var script = document.createElement(‘script’);
script.src = someJs;
document.body.appendChild(script);
}
}());