<input type="button" value="點選" id="btn"/>
<script src="commer.js"></script>
<script>
    //為同一個元素繫結不同的事件指向同一個事件的處理函式
    ver("btn").onclick=f1;
    ver("btn").onmouseover=f1;
    ver("btn").onmouseout=f1;
    function f1(e) {
        switch (e.type) {
            case "click":
                alert("好帥噢");
                break;
            case "mouseover":
                this.style.backgroundColor="red";
                break;
            case "mouseout":
                this.style.backgroundColor="green";
                break;
        }
    }
</script>