jQuery Simple Example
HTML
<script src="//www.addressfinder.co.nz/assets/v2/widget.js"></script>
<select class="myClass" data-val="true" id="sampleSelect" name="sampleSelect">
<option value="">Select an option</option>
<option value="1">1</option>
<option value="2">2</option>
<option value="3" selected="selected">3</option>
</select>
JavaScript
$(function() {
$('#sampleSelect').change(function () {
var test = $('#sampleSelect').val();
alert(test)
});
});