loadscripts.js

function loadScripts(assets, nostore) {
  if (!('async' in document.createElement('script'))) {
    assets.forEach(function (asset) {
      document.write('<script src="' + asset.url + '"><\/script>');
    });
    return;
  }

  if (!nostore) {
    var valid = assets.every(function (asset) {
      var cache = localStorage.getItem(asset.key);
      if (cache) {
        var index = cache.indexOf('|');
        if (cache.substr(0, index) === asset.url) {
          asset.content = cache.substr(index + 1);
          return true;
        }
      }
    });
    if (valid) {
      setTimeout(function fn() {
        if (document.readyState === 'complete') {
          assets.forEach(function (asset) {
            var script = document.createElement('script');
            script.innerHTML = asset.content;
            document.head.appendChild(script);
          });
        }
        else {
          setTimeout(fn, 50);
        }
      }, 50);
      return;
    }
  }

  assets.forEach(function (asset) {
    var script = document.createElement('script');
    script.onload = function () {
      var xhr = new XMLHttpRequest();
      xhr.open('GET', asset.url);
      xhr.onload = function() {
        try {
          localStorage.setItem(asset.key, asset.url + '|' + xhr.responseText);
        }
        catch (e) {}
      };
      xhr.send();
    };
    script.crossorigin = true;
    script.async = false;
    script.src = asset.url;
    document.body.appendChild(script);
  });
}