关闭/隐藏div

<script type="text/javascript">
        function openPOP(e) {
            document.getElementById("pop").style.display = "block";
            e = e || window.event;
            stopEvent(e);
        }
        document.onclick = function() {
            document.getElementById("pop").style.display = "none";
        }
        window.onload = function() {
            document.getElementById("pop").onclick = function(e) {
                e = e || window.event; stopEvent(e); } } //阻止事件冒泡
        var stopEvent = function(e) {
            if (e.stopPropagation) { e.stopPropagation(); } else { e.cancelBubble = true; }
        }
    </script>

    <style type="text/css">
        #pop
        {
            border: 1px solid black;
            width: 100px;
            height: 100px;
            display: none;
            position: absolute;
            left: 200px;
            background-color: #eee;
        }
    </style>
    <div id="pop">
        I'm POP
    </div>
    <input type="button" value="pop" onclick="openPOP(event);" />