Boolean()類型轉換

Boolean(value) 是把值轉換成Boolean類型

example

var b1 = Boolean("");//返回false,空字符串
var b2 = Boolean("s");//返回true，非空字符串
var b3 = Boolean(0);//返回false，數字0
var b4 = Boolean(1);//返回true，非0數字
var b5 = Boolean(-1);//返回true，非0數字
var b6 = Boolean(null);//返回false
var b7 = Boolean(undefined);//返回false
var b8 = Boolean(new Object());//返回true，對象

    function test() {
         alert(' emmm..');
    }
        console.log(typeof test);
        console.log(Boolean(test));

typeof判斷test為function
Boolean轉換為true

function test(can) {
         alert(' emmm..');
    }
        console.log(typeof test());
        console.log(Boolean(test()));

typeof判斷test()方法為undefined
Boolean轉換為false