js之循环语句 

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
//js中有两种for循环
//第一种循环的是下标和key
<script>
    var a=[11,22,33,44]
    for (var item in a){
        //循环的是a的索引
       console.log(a[item])
    }
    //循环字典操作
    var b={"k1":"v1","k2":"v2",}
    for (var item in b){
       console.log(b[item])
    }

</script>
//for循环产生下标 不支持字典操作
<script>
    var a=[11,22,33,44]
    for (var i =0;i<a.length;i++){
        console.log(a[i])
    }


</script>


</body>
</html>

　　

posted @ 2018-09-28 21:12  random_lee  阅读(502)  评论(0)  编辑  收藏  举报