click event select option jquery
$('#mySelect').on('change', function() {
var value = $(this).val();
alert(value);
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.0/jquery.min.js"></script>
<select id="mySelect">
<option value='1'>1</option>
<option value='2'>2</option>
<option value='3'>3</option>
<option value='4'>4</option>
<option value='5'>5</option>
<option value='6'>6</option>
<option value='7'>7</option>
<option value='8'>8</option>
</select>