function dynamicallyLoadScript(url) {
    var script = document.createElement("script");
    script.src = url;
    document.head.appendChild(script);
}

dynamicallyLoadScript('https://cdnjs.cloudflare.com/ajax/libs/mark.js/8.11.1/jquery.mark.es6.min.js')

ref:

How do I include a JavaScript file in another JavaScript file? – Stack Overflow