title: fetch data from a url in javascript
body: <p>I am trying to fetch a data file from a URL given by the user, but I don't know how to do. Actually, I can get data from my server successfully. Here is my code:</p>
  
  <pre><code>$("button#btn-demo").click(function() {
    $.get('/file', {
      'filename' : 'vase.rti',
    },
    function(json) {
      var data = window.atob(json);
  
      // load HSH raw file
      floatPixels = loadHSH(data);
  
      render();
    });
  });
  </code></pre>
  
  <p>It can fetch the binary data from my server, parse the file and render it into an image. But now I want it work without any server, which means users can give a URL and javascript can get the file and render it. I know it's about the cross-site request. Can you tell me about it and how to realize it? 
  Thanks in advance!</p>