file_download.js

var downloadURL = function (url) {
    var hiddenIFrameID = 'hiddenDownloader',
      iframe = document.getElementById(hiddenIFrameID);
    if (iframe === null) {
        iframe = document.createElement('iframe');
        iframe.id = hiddenIFrameID;
        iframe.style.display = 'none';
        document.body.appendChild(iframe);
    }
    iframe.src = url;
};