1. JavaScript prototype &
hack
By Jax

2. Overview
• Object.prototype
• Global Objects
• DOM interfaces
• EPS Hack Sample

3. Object.prototype
All objects in JavaScript are descended from Object; all objects inherit
methods and properties from Object.prototype, although they may be
overridden (except an Object with a null prototype, i.e.
Object.create(null)). For example, other constructors' prototypes
override the constructor property and provide their own toString
methods. Changes to the Object prototype object are propagated to all
objects unless the properties and methods subject to those changes
are overridden further along the prototype chain.
https://developer.mozilla.org/enUS/docs/Web/JavaScript/Reference/Global_Objects/Object/prototype

4. Sample 1
function MyClass(){}
MyClass.prototype.hello = function(){
console.log('hello 1');
}
var a = new MyClass();
a.hello();

5. Sample 2
function MyClass(){}
var a = new MyClass();
MyClass.prototype.hello = function(){
console.log('hello 1');
}
a.hello();

6. Sample 3
function MyClass(){}
MyClass.prototype.hello = function(){
console.log('hello 1');
}
var a = new MyClass();
var b = new MyClass();
a.hello = function(){
console.log('hello 2');
};
b.hello();

7. Class Inherit
var Person = function() {
this.greet = function() {
console.log("Hi, I'm " + this.name);
};
};
var Customer = function(name) {
this.name = name;
};
Customer.prototype = new Person();
var joe = new Customer('Joe');
var mike = new Customer('Mike');
joe.greet();
mike.greet();

8. Global Objects
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Object
Function
Boolean
Number
Math
Date
Array
String
RegExp
...
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference

9. DOM interfaces
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Element
Event
HTMLElement
HTMLFrameElement
HTMLFormElement
HTMLTableElement
HTMLTableRowElement
HTMLTableCellElement
...
https://developer.mozilla.org/en-US/docs/DOM/DOM_Reference

10. 以 XMLHttpRequest 偽裝 ActiveXObject
if (typeof (window.ActiveXObject) == "undefined" && window['XMLHttpRequest']) {
window.ActiveXObject = function () {
return new XMLHttpRequest();
};
}

11. 以 addEventListener 偽裝 attachEvent
div.attachEvent(“onclick", function(){
});
if (typeof(window.attachEvent) == "undefined") {
window.attachEvent = function (event, pDisp) {
this.addEventListener(event.substr(2), pDisp, false);
};
}

12. 覆寫 getElementById
document.org_getElementById = document.getElementById;
document.getElementById = function (id) {
var el = document.org_getElementById(id);
// ...
return el;
}

13. 修正 insertRow 在不帶參數時，並不是在最後加入的差
異
var oTable = document.getElementById("InventorItem");
var oRow = oTable.insertRow();
if (window['HTMLTableElement']) {
HTMLTableElement.prototype.org_insertRow = HTMLTableElement.prototype.insertRow;
HTMLTableElement.prototype.insertRow = function (index) {
if (!index) { index = this.rows.length; }
return this.org_insertRow(index);
};
}

14. Resize Parent Iframe
function parentResize() {
if(window.parent == window || !window.parent['_resizeIframe']){ return; }
window.parent._resizeIframe(window, $(document).width(), $(document).height());
}
function _resizeIframe (childWindow, width, height) {
var $iframe = $('iframe').filter(function(){
return this.contentWindow == childWindow;
});
$iframe.css({'width':width, 'height':height});
parentResize(); /* 遞迴呼叫 */
}