1. 基于已有对象扩充其对象和方法(只适合于临时的生成一个对象):
<html> <head> <title>基于已有对象扩充其对象和方法(只适合于临时的生成一个对象)</title> </head> <script> var obj = new Object(); obj.name="userObject"; obj.printName = function(name){ this.name = name; alert(this.name); } obj.printName("newUserObject"); </script> <body> </body> </html>
2.工厂方式创建对象(每次创建一个object后,其中对应的方法(本例中是get)也被创建一次,方法不能被所创建的所有对象(本例中是obj1和obj2)共享):
a.
<html> <head> <title>工厂方式创建对象</title> </head> <script> function createObject(){ var obj = new Object(); obj.name="userObject"; obj.password = "12345"; obj.get = function(){ alert(this.name + ", " + this.password); } return obj; } var obj1 = createObject(); var obj2 = createObject(); obj1.get(); obj2.get(); </script> <body> </body> </html>
b.带参数的构造方法:
<html> <head> <title>工厂方式创建对象</title> </head> <script> function createObject(username,password){ var obj = new Object(); obj.username = username; obj.password = password; obj.get = function(){ alert(this.username + ", " + this.password); } return obj; } var obj1 = createObject("zhangsan","123456"); obj1.get(); </script> <body> </body> </html>
c.让函数被多个创建的对象所共享,而不是每一个对象都创建一个相同的函数(缺点:对象定义本身和方法分离了):
<html> <head> <title>工厂方式创建对象</title> </head> <script> function get(){ alert(this.username + ", " + this.password); } function createObject(username,password){ var obj = new Object(); obj.username = username; obj.password = password; obj.get = get; return obj; } var obj1 = createObject("zhangsan","123456"); var obj2 = createObject("lisi","54321"); obj1.get(); obj2.get(); </script> <body> </body> </html>
3.构造函数方式:
a.
<html> <head> <title>构造函数方式创建对象</title> </head> <script> function Person(){ this.username = "zhangsan"; this.password = "123"; this.getInfo = function(){ alert(this.username + ", " + this.password); } } var person = new Person(); person.getInfo(); </script> <body> </body> </html>
b.可以在构造函数是传递参数:
<html> <head> <title>构造函数方式创建对象</title> </head> <script> function Person(username,password){ this.username = username; this.password = password; this.getInfo = function(){ alert(this.username + ", " + this.password); } } var person = new Person("zhangsan","123"); person.getInfo(); </script> <body> </body> </html>
4.使用原型(prototype)方式创建对象:
优点:创建的多个对象共享同一个方法(getInfo)
缺点:创建的多个对象在共享同一个方法的同时也共享了同样的属性(username,password),实际开发中这样儿是不行的,必须是多个对象都要有自己的属性。
采用该方式创建对象通常是用来扩展已有对象的某一个方法。
a.
<html> <head> <title>使用原型(prototype)方式创建对象</title> </head> <script> function Person(){} Person.prototype.username = "zhangsan"; Person.prototype.password = "123"; Person.prototype.getInfo = function(){ alert(this.username + ", " + this.password); } var person = new Person(); var person2 = new Person(); person.username = "lisi"; person.getInfo(); person2.getInfo(); </script> <body> </body> </html>
b.如果使用原型方式创建对象,那么生成的所有对象将会共享原型中的属性,这样儿一个对象改变了该属性也会反应到其他的对象上:
<html> <head> <title>使用原型(prototype)方式创建对象</title> </head> <script> function Person(){} Person.prototype.username = new Array(0); Person.prototype.password = "123"; Person.prototype.getInfo = function(){ alert(this.username + ", " + this.password); } var person = new Person(); var person2 = new Person(); person.username.push("zhangsan"); person.username.push("lisi"); person.password = "456"; person.getInfo(); person2.getInfo(); </script> <body> </body> </html>
c.使用原型和构造函数方式来创建对象:
<html> <head> <title>使用原型(prototype)方式创建对象</title> </head> <script> function Person(){ this.username = new Array(); this.password = "123" } Person.prototype.getInfo = function(){ alert(this.username + ", " + this.password); } var person = new Person(); var person2 = new Person(); person.username.push("zhangsan"); person.username.push("lisi"); person.getInfo(); person2.getInfo(); </script> <body> </body> </html>
5.动态原型方式:在构造函数中通过标志量让所有对象共享一个方法,而每个对象拥有自己的属性。
<html> <head> <title>动态原型方式:在构造函数中通过标志量让所有对象共享一个方法,而每个对象拥有自己的属性</title> </head> <script> function Person(){ this.username = "zhangsan"; this.password = "123"; if(typeof Person.flag == "undefined"){ Person.prototype.getInfo = function(){ alert(this.username + ", " + this.password); } Person.flag = true; } } var p = new Person(); var p2 = new Person(); p.getInfo(); p2.getInfo(); p.username="lisi"; p.getInfo(); p2.getInfo(); </script> <body> </body> </html>