JavaScript--隐式转换 

 1 <script>
 2     "use strict";
 3     var data1 = 0,
 4         data2 = "",
 5         data3 = false,
 6         data4 = undefined,
 7         data5 = null;
 8     // 下面全部为false
 9     console.log(!!data1);
10     console.log(Boolean(data1)); 
11     console.log(Boolean(data2));
12     console.log(Boolean(data3));
13     console.log(Boolean(data4));
14     console.log(Boolean(data5));
15 </script>
16 
17 <script>
18     "use strict";
19 
20     var num= "8000";
21     console.log(num);       // "8000"
22     console.log(+num);      //  8000
23     console.log(-num);      //  -8000
24     console.log(num - 100); //  7900
25     console.log(num + 100); //  8000100
26 </script>

 

posted @ 2017-10-14 10:24  QinXiao.Shou  阅读(110)  评论(0)    收藏  举报