Triggering Click Event on File Input with jQuery
<blockquote>
  <p><strong>Possible Duplicate:</strong><br>
  <a href="http://stackoverflow.com/questions/793014/jquery-trigger-file-input">Jquery trigger file input</a>  </p>
</blockquote>



<p>I'm developing an app that needs the user to specify a file from the very beginning. I would like to have the file input box display immediately, instead of requiring the user to click an upload button.</p>

<p>Can someone explain to me why the third option works in my jsfiddle example while the others don't? Links to official specs would be most appreciated.</p>

<p><a href="http://jsfiddle.net/vnS3k/" rel="nofollow">http://jsfiddle.net/vnS3k/</a></p>

<pre><code>// Trigger Click Event at Load - Doesn't Work
$('#a').click();

// Trigger Click Event at Timeout - Doesn't Work
window.setTimeout(function() {
    $('#a').click();
}, 3000);

// Trigger Click Event at User Click *On Something Else* - Works
$('#b').click(function() {
    $('#a').click();
});
</code></pre>
