vsjsonp.js

// VSJONP ― Very Simple JSONP
// ==========================
//
// Usage:
//   fetchJsonP({ 
//     url:      'http://shit-no-cors.json', 
//     complete: function(response) {
//       console.log(response);
//     }
//   });

var fetchJsonP = function(options) {
  var options = options ? options : {},
      script = document.createElement('script');
  functionName = 'jsonp' + Math.floor(Math.random() * 9999);
  window[functionName] = function(response) {
     if (options.complete) options.complete(response);
  }
  script.src = options.url + "&callback=" + functionName;
  script.onload = function() {
    document.body.removeChild(script);
    delete window[functionName];
  }
}