small jsonp

main.js

(function(doc, script){
  var API_KEY = ''; // use yours
  
  // tks -- http://css-tricks.com/thinking-async/ 
  var js, 
      fjs = doc.getElementsByTagName(script)[0],
      add = function(url, id) {
        if (doc.getElementById(id)) {return;}
        js = doc.createElement(script);
        js.src = url;
        id && (js.id = id);
        fjs.parentNode.insertBefore(js, fjs);
      };

  /* CODE FOR JSONP request, using Tumblr as example*/
  var url,
      ts = (new Date).getTime(),
      cb = 'jsonp_'+ts,
      
      // vars used later as params, adjust for your needs
      apiKey       = API_KEY,
      apiBase      = 'http://api.tumblr.com/v2/blog/',
      baseHostName = window.location.host;
  
  window[cb] = handleResponse;
  function handleResponse(data){
    console.log(data);
  }
  
  // adapt for your needs
  url = [
    apiBase, 
    baseHostName, 
    '/posts?api_key=',
    apiKey,
    '&type=photo',
    '&tag=responsive',
    '&callback='+callbackName,
    '&cacheBust='+ (new Date).getTime()
  ].join('');
  
  add(url);
  /* END JSONP */      
})(document, 'script');