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>