Click the button to display an alert box.

<button onclick="myFunction()">Try it</button>
<input type="text" id="checkin" class="test" autocomplete="off" name="arrival" value="">
<input type="text" id="checkout" class="test" autocomplete="off" name="departure" value="">

<form method="post" action="https://hotels.cloudbeds.com/reservas/jyTWBZ" input="" type="hidden" name="date_format" value="d/m/Y">

</form>