WordPress
1、进入WordPress网站后台

2、选择外观-小工具-添加自定义html小工具。

3、填写如下代码：

<div class="gn_box">
    <h1><center><font color=#E80017>2</font><font color=#D1002E>0</font><font color=#BA0045>2</font><font color=#A3005C>0</font><font
            color=#8C0073>年</font><font color=#75008A>-</font><font color=#5E00A1>新</font><font
            color=#4700B8>年</font><font color=#3000CF>倒</font><font color=#1900E6>计</font><font color=#0200FD>时</font>
    </center></h1>
    <center>
        <div id="CountMsg" class="HotDate">
            <span id="t_d">157 天</span>
            <span id="t_h">9 时</span>
            <span id="t_m">7 分</span>
            <span id="t_s">42 秒</span>
        </div>
    </center>
    <script type="text/javascript"> function getRTime() {
        var EndTime = new Date('2020/01/25 00:00:00');
        var NowTime = new Date();
        var t = EndTime.getTime() - NowTime.getTime();
        var d = Math.floor(t / 1000 / 60 / 60 / 24);
        var h = Math.floor(t / 1000 / 60 / 60 % 24);
        var m = Math.floor(t / 1000 / 60 % 60);
        var s = Math.floor(t / 1000 % 60);
        document.getElementById("t_d").innerHTML = d + " 天";
        document.getElementById("t_h").innerHTML = h + " 时";
        document.getElementById("t_m").innerHTML = m + " 分";
        document.getElementById("t_s").innerHTML = s + " 秒";
    }
    setInterval(getRTime, 1000);
    </script>
</div>

4、点击保存，即可前台浏览查看。

其他网站
1、复制如下代码：

<div class="gn_box">
    <h1><center><font color=#E80017>2</font><font color=#D1002E>0</font><font color=#BA0045>2</font><font color=#A3005C>0</font><font
            color=#8C0073>年</font><font color=#75008A>-</font><font color=#5E00A1>新</font><font
            color=#4700B8>年</font><font color=#3000CF>倒</font><font color=#1900E6>计</font><font color=#0200FD>时</font>
    </center></h1>
    <center>
        <div id="CountMsg" class="HotDate">
            <span id="t_d">157 天</span>
            <span id="t_h">9 时</span>
            <span id="t_m">7 分</span>
            <span id="t_s">42 秒</span>
        </div>
    </center>
    <script type="text/javascript"> function getRTime() {
        var EndTime = new Date('2020/01/25 00:00:00');
        var NowTime = new Date();
        var t = EndTime.getTime() - NowTime.getTime();
        var d = Math.floor(t / 1000 / 60 / 60 / 24);
        var h = Math.floor(t / 1000 / 60 / 60 % 24);
        var m = Math.floor(t / 1000 / 60 % 60);
        var s = Math.floor(t / 1000 % 60);
        document.getElementById("t_d").innerHTML = d + " 天";
        document.getElementById("t_h").innerHTML = h + " 时";
        document.getElementById("t_m").innerHTML = m + " 分";
        document.getElementById("t_s").innerHTML = s + " 秒";
    }
    setInterval(getRTime, 1000);
    </script>
</div>

2、把代码粘贴至你认为合适的地方即可

3、保存，前台浏览即可。