download multiple files and save as zip bundle

by dshilkret

HTML

<script src="https://rawgit.com/eligrey/FileSaver.js/master/FileSaver.min.js"></script>
<script src="https://rawgit.com/Stuk/jszip/master/dist/jszip.min.js"></script>
<progress type="range" id="p1" min=0 max=1>

JavaScript

(function (global, factory) {
  if (typeof define === "function" && define.amd) {
    define([], factory);
  } else if (typeof exports !== "undefined") {
    factory();
  } else {
    var mod = {
      exports: {}
    };
    factory();
    global.FileSaver = mod.exports;
  }
})(this, function () {
  "use strict";

  /*
  * FileSaver.js
  * A saveAs() FileSaver implementation.
  *
  * By Eli Grey, http://eligrey.com
  *
  * License : https://github.com/eligrey/FileSaver.js/blob/master/LICENSE.md (MIT)
  * source  : http://purl.eligrey.com/github/FileSaver.js
  */
  // The one and only way of getting global scope in all environments
  // https://stackoverflow.com/q/3277182/1008999
  var _global = typeof window === 'object' && window.window === window ? window : typeof self === 'object' && self.self === self ? self : typeof global === 'object' && global.global === global ? global : void 0;

  function bom(blob, opts) {
    if (typeof opts === 'undefined') opts = {
      autoBom: false
    };else if (typeof opts !== 'object') {
      console.warn('Deprecated: Expected third argument to be a object');
      opts = {
        autoBom: !opts
      };
    } // prepend BOM for UTF-8 XML and text/* types (including HTML)
    // note: your browser will automatically convert UTF-16 U+FEFF to EF BB BF

    if (opts.autoBom && /^\s*(?:text\/\S*|application\/xml|\S*\/\S*\+xml)\s*;.*charset\s*=\s*utf-8/i.test(blob.type)) {
      return new Blob([String.fromCharCode(0xFEFF), blob], {
        type: blob.type
      });
    }

    return blob;
  }

  function download(url, name, opts) {
    var xhr = new XMLHttpRequest();
    xhr.open('GET', url);
    xhr.responseType = 'blob';

    xhr.onload = function () {
      saveAs(xhr.response, name, opts);
    };

    xhr.onerror = function () {
      console.error('could not download file');
    };

    xhr.send();
  }

  function corsEnabled(url) {
    var xhr = new XMLHttpRequest(); // use sync to avoid popup blocker

    xhr.open('HEAD',...