title: New Typescript 1.8.4 build error: " Build: Property 'result' does not exist on type 'EventTarget'. "
body: <p>I am New to typescript. In my Durandal application I migrated to VS-2012 to VS-2015 means typescript 0.9 to typescript 1.8.4. After migrated I got so many build errors. I resolved all those except one. I am getting below build error on types of Events.</p>
  
  <p><strong>ERROR: " Build: Property 'result' does not exist on type 'EventTarget' "</strong></p>
  
  <p>And the code was exactly like this below:</p>
  
  <pre><code>var reader:any,
  target:EventTarget;
  
  reader= new FileReader();
  reader.onload = function (imgsrc){
      var fileUrl = imgsrc.target.result;
  }
  </code></pre>
  
  <p>"Imgsrc" is taking type event.</p>
  
  <p>It's working fine with typescript 0.9 but with 1.8.4 it's throwing error as 'result' does not exist on type 'EventTarget'. 
  Can any one help on this to resolve.</p>
  
  <p><strong>Note: "target:EventTarget" is getting from lib.d.ts</strong></p>