1.js創(chuàng)建對(duì)象常用的方式
1.混合的構(gòu)造函數(shù)，原型方式（推薦）：
function myObject(args){
//對(duì)象屬性
this.args = args;
}
//對(duì)象方法
myObject.prototype.func = function(){
alert(this.args);
};
//實(shí)例化對(duì)象并調(diào)用方法
var myObj = new myObject('hello world');
myObj.func();
2.工廠方式
function myObject(){
var obj = new Object();
obj.name = 'Jack';
obj.func = function(){
alert(this.name);
}
return obj;
}
//實(shí)例化對(duì)象并調(diào)用方法
//這里不要用new關(guān)鍵字
var myOb = myObject();
myOb.func();
3.構(gòu)造函數(shù)方式
function myObj(){
this.name = 'Jack';
this.func = function(){
alert(this.name)
}
}
//實(shí)例化對(duì)象并調(diào)用方法
var myOb = new myObj();
myOb.func();
4.原型方式
function myObj(){}
myObj.prototype.name = 'Jackson';
myObj.prototype.age = 25;
myObj.prototype.func = function(){
alert('my name is '+this.name+',i am '+this.age+'years old');
}
//實(shí)例化對(duì)象并調(diào)用方法
var myOb = new myObj();
myOb.func();
2.js面向?qū)ο蟮睦^承
//拷貝繼承,obj1繼承obj2
function extend(obj1,obj2){
for(var attr in obj2){
obj1[attr] = obj2[attr];
}
}
function Person(name,age){
this.name = name;
this.age = age;
}
Person.prototype.func = function(){
alert(this.name);
}
function Player(name,age,job){
//屬性繼承，call改變this指向問(wèn)題
Person.call(this,name,age);
this.job= job;
}
//方法的繼承，for in ,拷貝繼承，改變Player的方法也不會(huì)污染到Person類，jq中也用拷貝繼承
extend(Player.prototype, Person.prototype);
p = new Player('姚明',35,'籃球運(yùn)動(dòng)員');
p.func();
alert(p.name+p.age+'歲'+p.job);
3.js用toString方法判斷數(shù)據(jù)類型
toString()：把對(duì)象轉(zhuǎn)為字符串
toString()：系統(tǒng)對(duì)象自帶的，自定義對(duì)象是通過(guò)原型鏈查找Object對(duì)象的
var num = 255;
num.toString(16);//轉(zhuǎn)換為16進(jìn)制，ff
var arr = [];
alert(arr.toString == Object.prototype.toString);//false;
function Aaa(){}
var a = new Aaa();
alert(a.toString == Object.prototype.toString);//ture
console.log(Object.prototype.toString.call(123)) //[object Number]
console.log(Object.prototype.toString.call('123')) //[object String]
console.log(Object.prototype.toString.call(undefined)) //[object Undefined]
console.log(Object.prototype.toString.call(true)) //[object Boolean]
console.log(Object.prototype.toString.call({})) //[object Object]
console.log(Object.prototype.toString.call([])) //[object Array]
console.log(Object.prototype.toString.call(function(){})) //[object Function]
//判斷是否為函數(shù)
function isFunction(it) {
return Object.prototype.toString.call(it) === '[object Function]';
}
//判斷是否為數(shù)組：
function isArray(o) {
return Object.prototype.toString.call(o) === '[object Array]';
}
