<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<script>
/*******************數字類型轉字符串*******************/
console.log('數字類型轉字符串');
var num = 1;
//方法一：
var num2 = num.toString();
//方法二：
var num3 = String(num);
//方法三：
var num4 = num + '';
//string
console.log(typeof num2);
console.log(typeof num3);
console.log(typeof num4);
/*******************字符串轉數字*******************/
console.log('字符串轉數字');
var str = '3.1415';
/*******轉換成數字並取整*******/
var str2 = parseInt(str);
//3
console.log(str2);
//number
console.log(typeof str2);
/*******轉換成浮點數*******/
var str3 = parseFloat(str);
//3.1415
console.log(str3);
//number
console.log(typeof str3);
/*******強制轉換*******/
var str4 = Number(str);
//3.1415
console.log(str4);
//number
console.log(typeof str4);
/*******算數運算*******/
var str5 = str-0;
//3.1415
console.log(str5);
//number
console.log(typeof str5);
/*******************轉換爲布爾值類型*******************/
console.log('轉換爲布爾值類型');
//false
console.log(Boolean(''));
//false
console.log(Boolean(0));
//true
console.log(Boolean(1));
//true
console.log(Boolean(10));
//false
console.log(Boolean(NaN));
//true(注意)
console.log(Boolean('false'));
//true
console.log(Boolean('true'));
//false
console.log(Boolean(null));
//false
console.log(Boolean(undefined));
//true
console.log(Boolean('hello world'));
</script>
</head>
<body>
</body>
</html>
