Simple jsonp

jsonp.js

function jsonp(src,cb){
  var script = document.createElement('script');
  var previousCall = document.getElementById('srvCall');
  previousCall && document.body.removeChild(previousCall);
  script.charset = 'UTF-8';
  script.id = 'srvCall';
  document.body.insertBefore(script, document.body.firstChild);
  script.src = src;
  window.serverCallback = cb;
}