A brief discussion on one of the function.apply ()------(function hijacking and object duplication) _javascript skills

On the inheritance of objects, the general practice is to use the Copy method: Object.extend

See Protpotype.js Implementation method:

Copy Code code as follows:

Object.extend = function (destination, source) {
For (property in source) {
Destination[property] = Source[property];
}
return destination;
}

In addition, there is a less common method: Function.apply.

Apply method can hijack (<<ajax in action>> book use "hijack" a language, very vivid AH) Another object of the method,
Inherits the properties of another object.
The model code is as follows:
Apply Demo Code

Copy Code code as follows:

<script>

function Person (name,age) {//Define a class, human
This.name=name//Name
This.age=age//Age
This.sayhello=function () {alert ("Hello")}
}

function Print () {//Show properties of Class
This.funcname= "Print"
This.show=function () {
var msg=[]
for (var key in this) {
if (typeof (This[key])!= "function") msg.push ([Key, ":", This[key]].join (""))
}
Alert (Msg.join ("\ n"))
}
}

function Student (name,age,grade,school) {//Student class
Person.apply (this,arguments)
Print.apply (this,arguments)
This.grade=grade//Grade
This.school=school//School
}

var p1=new person ("Jake", 10)
P1.sayhello ()

var s1=new Student ("Tom", 13, 6, "Tsinghua Primary School")
S1.show ()
S1.sayhello ()
Alert (S1.funcname)
</script>

The student class does not have any method, but after person.apply (this,arguments), he has the SayHello method of the person class and
All properties. The show () method is automatically obtained after print.apply (this,arguments).


This article, as a trigger, only on the use of application (in object inheritance and function hijacking aspects) to do a small demonstration, other more in-depth applications to
It's up to everyone to understand.