lovecoding
/
W250913


			
				
					
						
						
							123456789101112131415161718192021222324252627282930313233343536373839404142
							<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box{
            width: 300px;
            height: 300px;
            background-color: #999;;
            position: fixed;
            top: 50%;
            left: 50%;
            margin-top: -150px;
            margin-left: -150px;
            color: #fff;
            font-weight: bold;
            font-size: 50px;
            text-align: center;
            line-height: 300px;
        }
    </style>
</head>
<body>
    <div class="box">
        <span class="num">10</span>
    </div>
    <script>
        var i = 10;
        var oNum = document.getElementsByClassName("num")[0];
        var timer = setInterval(function(){
            i--;
            console.log(i);
            oNum.innerText = i;
            if(i==0){
                clearInterval(timer);
            }
        },1000)
    </script>
</body>
</html>