index.js

/**
 * Module dependencies.
 */

var is = require('is');
var onload = require('script-onload');
var tick = require('next-tick');

/**
 * Expose `loadScript`.
 *
 * @param {Object} options
 * @param {Function} fn
 * @api public
 */

module.exports = function loadIframe(options, fn){
  if (!options) throw new Error('Cant load nothing...');

  // Allow for the simplest case, just passing a `src` string.
  if (is.string(options)) options = { src : options };

  var https = document.location.protocol === 'https:' ||
              document.location.protocol === 'chrome-extension:';

  // If you use protocol relative URLs, third-party scripts like Google
  // Analytics break when testing with `file:` so this fixes that.
  if (options.src && options.src.indexOf('//') === 0) {
    options.src = https ? 'https:' + options.src : 'http:' + options.src;
  }

  // Allow them to pass in different URLs depending on the protocol.
  if (https && options.https) options.src = options.https;
  else if (!https && options.http) options.src = options.http;

  // Make the `<iframe>` element and insert it before the first iframe on the
  // page, which is guaranteed to exist since this Javaiframe is running.
  var iframe = document.createElement('iframe');
  iframe.src = options.src;
  iframe.width = options.width || 1;
  iframe.height = options.height || 1;
  iframe.style.display = 'none';

  // If we have a fn, attach event handlers, even in IE. Based off of
  // the Third-Party Javascript script loading example:
  // https://github.com/thirdpartyjs/thirdpartyjs-code/blob/master/examples/templates/02/loading-files/index.html
  if (is.fn(fn)) {
    onload(iframe, fn);
  }

  tick(function(){
    // Append after event listeners are attached for IE.
    var firstScript = document.getElementsByTagName('script')[0];
    firstScript.parentNode.insertBefore(iframe, firstScript);
  });

  // Return the iframe element in case they want to do anything special, like
  // give it an ID or attributes.
  return iframe;
};