title: Crossdomain JSONP with text file and hard-coded callback
body: <p>I know it is popular problem and people solves it by writing a proxy on the server side. But I want to avoid it, I have a file with hard-coded callback <code>jsonResponse()</code>:</p>
  
  <pre><code>jsonpResponse({"keys": ["0", "2", "3", "4", "5", "6"], "promoted": [3, 10, 44, 47, 47, 31], "upcoming": [187, 14, 285, 366, 322, 225]});
  </code></pre>
  
  <p>and I want to get it from another domain with <code>JQuery.ajax()</code>:</p>
  
  <pre><code>$.ajax({
    type: "GET",
    url: URL + filename, 
    dataType: "text jsonp",
    jsonpCallback: "jsonpResponse",
    success: function(data) {
      // wrapping data
    }
  });
  </code></pre>
  
  <p>and I get an error:</p>
  
  <pre><code>XMLHttpRequest cannot load http://first.domain/filename.jsonp. 
  Origin http://second.domain is not allowed by Access-Control-Allow-Origin.
  </code></pre>
  
  <p>Is there any way to do what I want that way? Do I really have to use a proxy? If it's true, than why?</p>