var per = new Object();
per.name = 'zhangsan';
per.age = ;
alert(per.name + per.age);

var per = new Object();
per.name = 'zhangsan';
per.age = ;
if per.hasOwnProperty('email'){
alert('具有email');
}else{
alert('无email');
}

function Person(){
}
Person.count = ;
var p = new Person();
Person.count++;
var p = new Person();
Person.count++;
var p = new Person();
Person.count++;
alert(Person.count);

function Person(){
Person.count++; //静态属性
Person.getCount=function(){ //静态方法
alert('当前共有' + Person.count + '个人');
}
}
Person.count = ;
var p = new Person();
var p = new Person();
var p = new Person();
Person.getCount();

function display(){
var i=; 
}
display();
//在这里，想访问局部变量i

//例
function fn(){
function fn(){
alert('hello');
}
return fn; //返回fn函数首地址
}
var test=fn(); //test也指向了fn函数的首地址
test();

//例
function fn(){
var i = ;
function fn(){
alert(i);
}
return fn; //返回fn函数首地址
}
var test=fn(); //test也指向了fn函数的首地址
test();

//例
function fn(){
var i = ;
function fn(){
alert(i++);
}
return fn; //返回fn函数首地址
}
var test=fn(); //test也指向了fn函数的首地址
test();
test();
test();

function Person(p_name){
var name = p_name;
this.age
}

function Person(p_name,p_age){
this.name = p_name;
var age = p_age;
}
var p = new Person('zhangsan',);
alert(p.name);
alert(p.age);

function Person(p_name,p_age){
this.name = p_name;
var age = p_age;
this.setAge=function(a){
age = a;
}
this.getAge=function(){
return(age);
}
}
var p = new Person('zhangsan',);
p.setAge();
alert(p.getAge());

Person(); //Person内的this指向window
var p=new Person(); //Person内的this指向p
per.Person(); //Person内的this指向per
function Person(p_name,p_age){
this.name = p_name;
this.age = p_age;
}
function speak(){
alert(this.name + this.age);
}
var p = new Person('zhangsan',);
//speak(); 这样调用this指向window
//p.speak(); p对象没有speak属性

function Person(p_name,p_age){
this.name = p_name;
this.age = p_age;
}
function speak(){
alert(this.name + this.age);
}
var p = new Person('zhangsan',);
speak.call(p);
speak.apply(p);

<script>
function fn(){
this.style.color='red';
}
function fn(){
this.style.fontSize='px';
}
window.onload=function(){
document.getElementById('btn').onclick=function(){
var div = document.getElementById('div');
fn.call(div);
fn.apply(div);
};
};
</script>
<div id='div'>hello javascript</div>
<input type='button' id='btn' value='确定'>

Object.prototype.方法=function(父类对象){
for(var i in 父类对象){
this[i] = 父类对象[i];
}　
};

Object.prototype.ext=function(parObject){
//循环遍历父类对象所有属性
for(var i in parObject){
//为子类对象添加这个遍历到的属性
//它的值是父类对象这个属性的属性值
this[i] = parObject[i];
}
}
function Person(p_name,p_age){
this.name=p_name;
this.age=p_age;
this.speak=function(){
alert(this.name+this.age);
}
}
function Student(p_no){
this.no=p_no;
this.say=function(){
alert(this.no+this.name_this.age);
}
}
var stu = new Student();
stu.ext(new Person('xiaoqiang',));
stu.speak();
stu.say();

function Person(p_name,p_age){
this.name=p_name;
this.age=p_age;
this.speak=function(){
alert(this.name+this.age);
}
}
function Student(p_no,p_name,p_age){
this.no=p_no;
this.say=function(){
alert(this.name+this.age+this.no);
}
Person.call(this,p_name,p_age);
}
var stu = new Student(,'zhagsan',);
stu.speak();
stu.say();

function Person(p_name,p_age){
this.name=p_name;
this.age=p_age;
this.speak=function(){
alert(this.name+this.age);
}
}
function Student(p_no){
this.no=p_no;
this.say=function(){
alert(this.name+this.age+this.no);
}
}
Student.prototype = new Person('wangwu',);
var stu = new Student();
stu.speak();
stu.say();