title: Property 'files' does not exist on type 'EventTarget' error in typescript
body: <p>I am trying to access the value of the input file from my ionic 2 application but still I'm facing the issue of property files does not exist on type 'EventTarget'.
  As it is properly working in js but not in typescript.
  The code is given below:</p>
  
  <pre><code>  document.getElementById("customimage").onchange= function(e?) {
              var files: any = e.target.files[0]; 
                EXIF.getData(e.target.files[0], function() {
                    alert(EXIF.getTag(this,"GPSLatitude"));
                });
            }
  </code></pre>
  
  <p>Please help me solve this issue as it is not building my ionic 2 application. </p>