JavaScriptでブラウザを閉じる方法

<button  id="exitSystem" onclick="CloseWebPage()">关闭</button>
        <script>
            function CloseWebPage() {
                if (navigator.userAgent.indexOf("MSIE") > 0) {
                    if (navigator.userAgent.indexOf("MSIE 6.0") > 0) {
                        window.opener = null; window.close();
                    }
                    else {
                        window.open(&#39;&#39;, &#39;_top&#39;); window.top.close();
                    }
                }
                else if (navigator.userAgent.indexOf("Firefox") > 0) {
                    window.location.href = &#39;about:blank &#39;; //火狐默认状态非window.open的页面window.close是无效的
                    //window.history.go(-2);
                }
                else {
                    window.opener = null;
                    window.open(&#39;&#39;, &#39;_self&#39;, &#39;&#39;);
                    window.close();
                }
            }
        </script>

<button style="margin-left: 500px" onclick="CloseWebPage()">退出</button>
<script>
    function CloseWebPage() {
        open(location, &#39;_self&#39;).close();
    }
</script>