The fifth module python learning _ javascripts

The fifth module python learning _ javascripts

A basic data types java

 

//  1number 数值类型
var a = 3;
var b = 1.23;
var c = -123;
var d = 0;
alert(typeof a); //number
alert(typeof b); //number
alert(typeof c); //number
alert(typeof d); //number

// 2 string 类型
var a = "aaaaa";
alert(typeof a);


// Boolean
var c = 3<=4;
alert(c)  // true
alert(typeof c) // boolean


//undefined
var x;
alert( x) //undefined
alert(typeof x)  //undefined


//空对象
var y = null;
alert(y);   // null
alert(typeof y); //object