setInterval 实现时钟功能

<p>手表</p>
<p id="demo"></p>
<script>
    var myVar = setInterval(function () {
        myTimer()
    }, 1000)

    function myTimer() {
        var d = new Date();
        var t = d.toLocaleTimeString();
        document.getElementById("demo").innerHTML = t;

    }
    
</script>