select 触发事件

 <select class="form-control js-example-basic-single" onchange="showQuery()"   id="select_id"  >
    <option qr=box1  value=20>option1</option>
    <option qr=box2  value=19>option2</option>
</select>

<script type="text/javascript">

function showQuery()
{
    alert($("#select_id").find("option:selected").attr("qr"))
}

</script>