分支和循环

流程控制：
　　

 1 <!DOCTYPE html>
 2 <html lang="en">
 3 <head>
 4     <meta charset="UTF-8">
 5     <title>Title</title>
 6     <script>
 7         'use strict';
 8 
 9         var age = 3;
10         if (age>3){
11             alert("haha")
12         }else if (age<3){
13             alert("sad")
14         }else {
15             alert("a");
16         }
17 
18 
19         // while循环，避免程序死循环
20         while(age<100){
21             age = age +1;
22             console.log(age);
23         }
24         //
25         do {
26             age = age +1;
27             console.log(age);
28         }while (age<100);
29 
30 
31         // //for 循环
32         for (let i = 0; i < 100 ; i++) {
33             console.log(i);
34         }
35 
36         //forEach
37 
38         var aa = [12,1231,23,12,31,23,12,3];
39         aa.forEach(function (value) {
40             console.log(value)
41         });
42 
43         //返回数组
44         for (let num of aa ) {
45             console.log(num);
46         }
47 
48         //返回aa的下标
49         for (var num in aa){
50             console.log(num)
51         }
52 
53     </script>
54 
55 </head>
56 <body>
57 
58 </body>
59 </html>
流程控制

 

posted @ 2022-03-29 16:27  doremi429  阅读(13)  评论(0)  编辑  收藏  举报