代码如下

<h2 style="text-align: center">
    <span id="momk"></span><span id="momk" style="color: #ff0000;"></span>
    <script type="text/javascript">
        function NewDate(str) {
            str = str.split('-');
            var date = new Date();
            date.setUTCFullYear(str[0], str[1] - 1, str[2]);
            date.setUTCHours(0, 0, 0, 0);
            return date;
        }

        function momxc() {
            var birthDay = NewDate("2021-1-12");
            var today = new Date();
            var timeold = today.getTime() - birthDay.getTime();
            var sectimeold = timeold / 1000
            var secondsold = Math.floor(sectimeold);
            var msPerDay = 24 * 60 * 60 * 1000;
            var e_daysold = timeold / msPerDay;
            var daysold = Math.floor(e_daysold);
            var e_hrsold = (daysold - e_daysold) * -24;
            var hrsold = Math.floor(e_hrsold);
            var e_minsold = (hrsold - e_hrsold) * -60;
            var minsold = Math.floor((hrsold - e_hrsold) * -60);
            var seconds = Math.floor((minsold - e_minsold) * -60).toString();
            document.getElementById("momk").innerHTML = "本站为广大站长服务了" + daysold + "天" + hrsold + "小时" + minsold + "分" + seconds + "秒";
            setTimeout(momxc, 1000);
        }

        momxc();
    </script>
    <style>
        #momk {
            animation: change 10s infinite;
            font-weight: 800;
        }

        @keyframes change {
            0% {color: #5cb85c; }
            25% { color: #556bd8; }
            50% { color: #e40707; }
            75% { color: #66e616; }
            100% { color: #67bd31; }
        }
    </style>
</h2>

也可直接引入

<div style="height:45px">
<iframe src="https://www.zanglikun.com/wp-content/uploads/html/runtime.html">
</iframe>
</div>