问如何在选择引导多选择的ckeckbox时发出警报？

EN

$('#example-getting-started').multiselect({
    onChange: function (element, checked) {
	if (checked === true) {
	   if ($(element).val() == "Proofs")  alert("proofs checked");
	}
   }
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-multiselect/0.9.13/css/bootstrap-multiselect.css"/>
<script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-multiselect/0.9.13/js/bootstrap-multiselect.min.js"></script>

<label>Particulars :</label>
<select id="example-getting-started" multiple="multiple">
	<option value="DS Form">DS Form</option>
	<option class="proof" value="Proofs">Proofs</option>
	<option value="Banners">Banners</option>
	<option value="IRCTC Form">IRCTC Form</option>
	<option value="R3 Form Returned">R3 Form Returned</option>
	<option value="Declaration Form">Declaration Form</option>
	<option value="Agent Declaration Form">Sub Agent Declaration Form</option>
	<option value="Old Tokens">Old Tokens</option>
	<option value="11">Registration Form </option>
	<option value="12">12</option>
</select>

$('#checkboxid').change(function() {
    if ($('#checkboxid').prop('checked')) {
        //checked - insert code here
    }
    else {
        //not checked - insert code here
    }
});