Establecer archivo permitido html
<!-- (IE 10+, Edge (EdgeHTML), Edge (Chromium), Chrome, Firefox 42+) -->
<input type="file" accept=".xls,.xlsx" />
Thoughtful Tapir
<!-- (IE 10+, Edge (EdgeHTML), Edge (Chromium), Chrome, Firefox 42+) -->
<input type="file" accept=".xls,.xlsx" />