title: HTML file input — "accept" attribute not working
body: <p>After reading through the <a href="https://stackoverflow.com/questions/181214/file-input-accept-attribute-is-it-useful">comments on this post</a>, I came up with the following syntax for the accept attribute:</p>
  
  <p><strong>Images</strong></p>
  
  <pre><code>&lt;input type="file" accept="image/jpeg, image/png, image/gif, .jpeg, .png, .gif"&gt;
  </code></pre>
  
  <p><strong>Audio</strong></p>
  
  <pre><code>&lt;input type="file" accept="audio/mpeg, audio/x-wav, .mp3, .wav"&gt;
  </code></pre>
  
  <p>This works perfectly on desktop browsers, but does not appear to filter files at all on iOS or Android.</p>
  
  <p>Are there any cross-browser solutions available?</p>