JSONP.js

/**
 * Implement JSONP
 * @param {string} url The URL to call.
 * @param {function} callback A callback function, called with a single data parameter.
 */

function jsonp(url, callback) {
  var callbackName = 'callback_' + Math.round(100000 * Math.random());

  window[callbackName] = function(data) {
    delete window[callbackName];
    document.body.removeChild(script);
    callback(data);
  };

  var script = document.createElement('script');
  script.src = url + (url.indexOf('?') >= 0 ? '&' : '?') + 'callback=' + callbackName;
  document.body.appendChild(script);
}