1 <!DOCTYPE html>
2 <html>
3 <head>
4 <meta charset="UTF-8">
5 <title></title>
6 <script type="text/javascript">
7
8 /*
9 * 将其他的数据类型转换为Boolean
10 * - 使用Boolean()函数
11 * - 数字 ---> 布尔
12 * - 除了0和NaN，其余的都是true
13 *
14 * - 字符串 ---> 布尔
15 * - 除了空串，其余的都是true
16 *
17 * - null和undefined都会转换为false
18 *
19 * - 对象也会转换为true
20 *
21 */
22
23 //除了0和NaN，其余的都是true
24
25 var a = 123;
26 a = Boolean(a);
27 console.log(a);//true
28 console.log(typeof a);//boolean
29
30
31 a = -123;
32 a = Boolean(a);
33 console.log(a);//true
34 console.log(typeof a);//boolean
35
36
37 a = Infinity;
38 a = Boolean(a);
39 console.log(a);//true
40 console.log(typeof a);//boolean
41
42 a = 0;
43 a = Boolean(a);
44 console.log(a);//false
45 console.log(typeof a);//boolean
46
47
48 a = NaN;
49 a = Boolean(a);
50 console.log(a);//false
51 console.log(typeof a);//boolean
52
53 //---------------------------------------------------------------------------------------------------
54
55 //除了空串，其余的都是true
56
57 a = " ";
58 a = Boolean(a);
59 console.log(a); //false
60 console.log(typeof a); //boolean
61
62 a = "abc";
63 a = Boolean(a);
64 console.log(a); //true
65 console.log(typeof a); //boolean
66
67 //-------------------------------------------------------------------------------------
68
69 //null和undefined都会转换为false
70
71 a = null;
72 a = Boolean(a);
73 console.log(a); //false
74 console.log(typeof a); //boolean
75
76 a = undefined;
77 a = Boolean(a);
78 console.log(a); //false
79 console.log(typeof a); //boolean
80
81
82
83 </script>
84 </head>
85 <body>
86 </body>
87 </html>