JS onchange事件

<select name="" id="yinliao">
    <option value="0">白开水</option>
    <option value="1">矿泉水</option>
    <option value="2">白酒</option>
    <option value="3">北冰洋</option>
    <option value="4">红茶</option>
</select>

<script type="text/javascript">
    //获取元素
    var drink = document.getElementById('yinliao');

    //绑定onchange事件 on当...时候  change 改变
    drink.onchange = function() {
        alert('我的值发生了改变!!!');
    }
</script>