(function(objs, opt){

  function Preload($, options){
    ...
  }

  Preload.prototype.run = function(){
  ...
  }

  window.Preload = Preload;

}(objs, opt));

new Preload(document.getElementsByClassName('xzprelod'),{
    type : 'circle',
    value : 95,
    direction : 'foward',
    timing : 300,
    caption : 'HTML'
  });

Uncaught ReferenceError: Preload is not defined
    at HTMLDocument.<anonymous> (script.js:28)

  <script src="js/xzpreload.js"></script>
  <script src="js/script.js"></script>