あなたの知らないJavaScript-Intem 37は対象の高級なプログラムに向かって設計します.

function Aaa(){
}

var a1 = new Aaa();

//alert( a1 instanceof Object );  //true


var arr = [];

alert( arr instanceof Array );//true;

//  toString       : 

/*var arr = [];

alert( Object.prototype.toString.call(arr) == '[object Array]' ); */ 
//'[object Array]'

alert( arr.constructor == Array );  

alert( arr instanceof Array );  

alert( Object.prototype.toString.call(arr) == '[object Array]' ); 

window.onload = function(){

    var oF = document.createElement('iframe');
    document.body.appendChild( oF );

    var ifArray = window.frames[0].Array;

    var arr = new ifArray();

    //alert( arr.constructor == Array );  //false

    //alert( arr instanceof Array );  //false

    alert( Object.prototype.toString.call(arr) == '[object Array]' );  //true   
};

function SuperType(){
    this.property = true;
}
SuperType.prototype.getSuperValue = function(){
    return this.property;
};

function SubType(){
    this.subproperty = false;
}
//   SuperType
SubType.prototype = new SuperType();
SubType.prototype.getSubValue = function (){
    return this.subproperty;
};

var instance = new SubType();
alert(instance.getSuperValue()); //true

alert(instance instanceof Object); //true
alert(instance instanceof SuperType); //true
alert(instance instanceof SubType); //true

alert(Object.prototype.isPrototypeOf(instance)); //true
alert(SuperType.prototype.isPrototypeOf(instance)); //true
alert(SubType.prototype.isPrototypeOf(instance)); //true

function SuperType(){
    this.property = true;
}
SuperType.prototype.getSuperValue = function(){
    return this.property;
};
function SubType(){
    this.subproperty = false;
}
//   SuperType
SubType.prototype = new SuperType();
//     ，          ，         。
SubType.prototype.getSubValue = function (){
    return this.subproperty;
};
    //         
    SubType.prototype.getSuperValue = function (){
        return false;
    };
    var instance = new SubType();
    alert(instance.getSuperValue()); //false

function SuperType(){
    this.property = true;
}
SuperType.prototype.getSuperValue = function(){
    return this.property;
};
function SubType(){
    this.subproperty = false;
}
//   SuperType
SubType.prototype = new SuperType();
//          ，          
SubType.prototype = {
    getSubValue : function (){
        return this.subproperty;
    },
    someOtherMethod : function (){
        return false;
    }
};
var instance = new SubType();
alert(instance.getSuperValue()); //error!

function SuperType(){
    this.colors = ["red", "blue", "green"];
}
function SubType(){
}
//   SuperType
SubType.prototype = new SuperType();

var instance1 = new SubType();
instance1.colors.push("black");
alert(instance1.colors); //"red,blue,green,black"

var instance2 = new SubType();
alert(instance2.colors); //"red,blue,green,black"

function SuperType(){
    this.colors = ["red", "blue", "green"];
}
function SubType(){
    //   SuperType
    SuperType.call(this);
}
var instance1 = new SubType();
instance1.colors.push("black");
alert(instance1.colors); //"red,blue,green,black"

var instance2 = new SubType();
alert(instance2.colors); //"red,blue,green"

function SuperType(name){
    this.name = name;
}
function SubType(){
    //   SuperType，        
    SuperType.call(this, "Nicholas");
    //    
    this.age = 29;
}

var instance = new SubType();
alert(instance.name); //"Nicholas";
alert(instance.age); //29

function SuperType(name){
    this.name = name;
    this.colors = ["red", "blue", "green"];
}
SuperType.prototype.sayName = function(){
    alert(this.name);
};

function SubType(name, age){
    //    
    SuperType.call(this, name);
    this.age = age;
}

//    
SubType.prototype = new SuperType();
SubType.prototype.constructor = SubType;
SubType.prototype.sayAge = function(){
    alert(this.age);
};

var instance1 = new SubType("Nicholas", 29);
instance1.colors.push("black");
alert(instance1.colors); //"red,blue,green,black"
instance1.sayName(); //"Nicholas";
instance1.sayAge(); //29

var instance2 = new SubType("Greg", 27);
alert(instance2.colors); //"red,blue,green"
instance2.sayName(); //"Greg";
instance2.sayAge(); //27

var a = {
    name : '  '
};

var b = a;

b.name = '  ';

alert( a.name );//  

var a = {
    name : '  '
};

//var b = a;
var b = {};
extend( b , a );    
b.name = '  ';
alert( a.name );    

function extend(obj1,obj2){
    for(var attr in obj2){
        obj1[attr] = obj2[attr];
    }
}

//   :        ，              (      )

//      :           call

//      : for in :       (jquery        extend)

function CreatePerson(name,sex){   //  
    this.name = name;
    this.sex = sex;
}
CreatePerson.prototype.showName = function(){
    alert( this.name );
};

var p1 = new CreatePerson('  ',' ');
//p1.showName();


function CreateStar(name,sex,job){  //  

    CreatePerson.call(this,name,sex);

    this.job = job;

}

//CreateStar.prototype = CreatePerson.prototype;

extend( CreateStar.prototype , CreatePerson.prototype );

CreateStar.prototype.showJob = function(){
};

var p2 = new CreateStar('   ',' ','  ');

p2.showName();


function extend(obj1,obj2){
    for(var attr in obj2){
        obj1[attr] = obj2[attr];
    }
}

<html>
<head>
    <title>    title>
    <style type="text/css">
        #div1{width: 100px;height: 100px;background: red;position: absolute;}
        #div2{width: 100px;height: 100px;background: blue;position: absolute;left: 100px;}
    style>
head>

<body>
<div id="div1">div>
<div id="div2">div>


<script type="text/javascript">

window.onload = function(){
    var d1 = new Drag('div1');
    d1.init();

    var d2 = new childDrag('div2');
    d2.init();
}


function Drag(id){
    this.obj = document.getElementById(id);//       
    this.disX = 0;//    
    this.disY = 0;//    
}

Drag.prototype.init = function(){//    
    var that = this;
    this.obj.onmousedown = function(e){
        var e = e || window.event;
        that.fnDown(e);

        document.onmousemove = function(e){
            var e = e || window.evnet;
            that.fnMove(e);
        }
        document.onmouseup = function(){
            that.fnUP();
        }
        return false;
    }

}

Drag.prototype.fnDown = function(e){
    //clientX          ，         
    //offsetLeft:             
    this.disX = e.clientX - this.obj.offsetLeft;//     obj    
    this.disY = e.clientY - this.obj.offsetTop;
}

Drag.prototype.fnMove = function(e){
    this.obj.style.left = e.clientX - this.disX + 'px';
    this.obj.style.top = e.clientY - this.disY +'px';
}

Drag.prototype.fnUP = function(){
    document.onmousedown= null;
    document.onmousemove = null;
}


//    ，      ，        ，          

function childDrag(id){
    Drag.call(this,id);//   call，apply
}

//    for in 
extend(childDrag.prototype,Drag.prototype);

//       
childDrag.prototype.fnMove = function(e){
    var leftX = e.clientX - this.disX;
    var topY = e.clientY - this.disY;
    var clientW = document.documentElement.clientWidth - this.obj.offsetWidth;
    var clientH = document.documentElement.clientHeight  - this.obj.offsetHeight;

    if (leftX < 0){
        leftX = 0;
    }else if (leftX >clientW) {
        leftX = clientW;
    }

    if (topY < 0 ) {
        topY = 0;
    }else if (topY> clientH) {
        topY = clientH;
    }

    this.obj.style.left = leftX + 'px';
    this.obj.style.top = topY + 'px';
}


function extend(obj1, obj2){//    
    for(var attr in obj2){
        obj1[attr] = obj2[attr];
    }
}

script>
body>
html>