 <p>(Based on <a href="http://stackoverflow.com/questions/8595389/programmatically-trigger-select-file-dialog-box">Programmatically trigger &quot;select file&quot; dialog box</a>)</p> <p>You call the hidden input button from the dat.GUI button's function.</p> <p>You need to use the jQuery library to make it work</p> <pre><code>&lt;input id="myInput" type="file" style="visibility:hidden" /&gt; &lt;script&gt; var params = { loadFile : function() { $('#myInput').click(); } }; var gui = new dat.GUI(); gui.add(params, 'loadFile'). name('Load CSV file'); &lt;/script&gt; </code></pre>