JavaScript prototype 属性

定义与用法
The prototype property allows you to add properties and methods to an
object.
prototype属性允许你向一个对象添加属性和方法
Syntax
语法
object.prototype.name=value
Example 1
实例
In this example we will show how to use the prototype property to add a
property to an object:
在下面的例子中，我们将演示如何用prototype属性来向一个对象增加一个属性：
<script type="text/javascript">
function employee(name,jobtitle,born)
{
this.name=name
this.jobtitle=jobtitle
this.born=born
}
var fred=new employee("Fred Flintstone","Caveman",1970)
employee.prototype.salary=null
fred.salary=20000
document.write(fred.salary)
</script>
The output of the code above will be:
输出结果为：
20000