include other js files in a js file

document.writeln("<script type='text/javascript' src='Script1.js'></script>");
document.writeln("<script type='text/javascript' src='Script2.js'></script>");

// module.js
export function hello() {
  return "Hello";
}

// main.js
import {hello} from 'module'; // or './module'
let val = hello(); // val is "Hello";

// jQuery
$.getScript('/path/to/imported/script.js', function()
{
    // script is now loaded and executed.
    // put your dependent JS here.
});