数字转字符串与字符串转数字
1 <!DOCTYPE html>
2 <html lang="en">
3 <head>
4 <meta charset="UTF-8">
5 <title>Title</title>
6 </head>
7 <body>
8
9 </body>
10 </html>
11 <script>
12 var num = 5;
13 console.log(num.toString()); // "5"
14 console.log(String(num)); //"5"
15 var num = 0;
16 console.log(num.toString()); //"0"
17 console.log(String(num)); //"0"
18
19 var num = null;
20 console.log(String(null)); // "null"
21 console.log(typeof String(null)); // string
22
23 var num = "8000dafdasdfa";
24 console.log(Number(num)); //NaN
25 console.log(typeof Number(num)); //number
26
27 var num1 = "0.0823.123aaa123";
28 console.log(Number(num1)); // NaN
29 console.log(parseInt(num1)); //0
30 console.log(parseFloat(num1)); //0.0823
31
32 //parseInt() 强制转换成数值整数型,不会四舍五入
33 //parseFloat() 会解析第一个,遇到第二个、或者非数字结束
34 </script>