prototype:
当每创建一个类的实例的时候，都要执行一次构造函数，函数中的属性和方法总会被重复创建，prototype可以很好的解决。当new一个function时，该对象的成员将自动的赋给所创建对象。prototype发生在函数体(构造器)执行之前。prototype的定义必须在new实例化对象之前，否则不会起作用。
<HTML>
<HEAD>
<TITLE>Test JavaScript Function example </TITLE>
</HEAD>
<BODY>
<script>
var userA;
var userB;
function User(name,age)
{
this.str_name = name;
this.str_age = age;
}
User.prototype.sayage = function()
{
alert(this.str_age);
}
function testUser()
{
userA = new User("Tomseon","27");
userA.sayage();
//userA.sayme(); //Prototype definition must before new instance of the object, otherwise they would not work
User.prototype.sayme = function()
{
alert(this.str_name);
}
userB = new User("mike","20");
userB.sayage();
userB.sayme();
}
</script>
<input type="reset" name="Submit" id="Button1" value="testUser" onclick="testUser()">
</BODY>
</HTML>
<HEAD>
<TITLE>Test JavaScript Function example </TITLE>
</HEAD>
<BODY>
<script>
var userA;
var userB;
function User(name,age)
{
this.str_name = name;
this.str_age = age;
}
User.prototype.sayage = function()
{
alert(this.str_age);
}
function testUser()
{
userA = new User("Tomseon","27");
userA.sayage();
//userA.sayme(); //Prototype definition must before new instance of the object, otherwise they would not work
User.prototype.sayme = function()
{
alert(this.str_name);
}
userB = new User("mike","20");
userB.sayage();
userB.sayme();
}
</script>
<input type="reset" name="Submit" id="Button1" value="testUser" onclick="testUser()">
</BODY>
</HTML>