javascriptはウェブページのカウントダウン効果を実現します.

<div class="timer" id="timer">
     <span style="color: black;">    :span><span class="clock" style="color: red;">60span><span style="color: black"> span>
div>

    <span style="color: #0000ff;">var</span> t = 60<span style="color: #000000;">;
    </span><span style="color: #0000ff;">var</span> time = document.getElementsByClassName("clock")[0<span style="color: #000000;">];

    </span><span style="color: #0000ff;">function</span><span style="color: #000000;"> time() {
        t</span>--<span style="color: #000000;">;
        time.innerHTML </span>=<span style="color: #000000;"> t;
        </span><span style="color: #0000ff;">if</span>(t <= 0<span style="color: #000000;">) {
            </span><span style="color: #008000;">//</span><span style="color: #008000;">   div</span>
            document.getElementById("timer").style.display = "none"<span style="color: #000000;">;
            clearInterval(inter);
        }
    }
    </span><span style="color: #0000ff;">var</span> inter = setInterval("time()", 1000<span style="color: #000000;">);
</span>