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// 6/2/2008 HanaDaddy  hanadaddy at gmail.com
 
/* SarahAjax is a very simple ajax class.
 * url: target url to call. It is usally dynamic script or a simple page return xml or text.
 */
function SarahAjax(url){
	this.url=url;
	this.reqobj ; 
	this.method="GET";
	this.async= true; //if false , the connection will be synchronous ( you have to wait for the reply)
	//this.action = function (obj) { }  // Success reply handler. : youre responsibilty 
	//this.error  = function (obj) { }  // Error reply handler : your responsiblity to implement.	
 
	this.sendRequest = function() {
		if(this.reqobj == null){
    			if (window.XMLHttpRequest) {
				this.reqobj = new XMLHttpRequest();
    			} else if (window.ActiveXObject) {
    				this.reqobj = new ActiveXObject("Microsoft.XMLHTTP");
    			}
		}
 
		if (!this.action){
			alert("SaraAjax:Action member function is not defined! We need the reply handler!");
			return;
		}
		this.reqobj.open(this.method, this.url, this.async);
 
		var sajaxreq = this; // this is necessary to access myself in the callback function
		this.reqobj.onreadystatechange = function() { sajaxreq.callback(); }
 
		this.reqobj.send(null);
	}
 
	this.callback = function () {
 
		if (this.reqobj.readyState == 4) {
			if (this.reqobj.status == 200) {
				//alert("reply is back?"+this.reqobj.responseText);
				this.action(this.reqobj);
			}else{
			 	//alert("There was a problem retrieving data:\n" + this.reqobj.statusText);
			 	if (this.error){
			 		this.error(this.reqobj);
			 	}
			}
		}		
	}	
}

function Person (firstname,lastname,age){
 
	this.firstname=firstname;
	this.lastname=lastname;
	this.age=age;
 
	this.introduction = function (type) {
		if (type=='simple'){
			alert("Hi, I am " + this.firstname +".");
		}else{
 
			alert("Hello, my name is "+this.firstname + " " + this.lastname+"." +
			 	" I am " + this.age + " years old.");
		}	
	}
 
}
 
var p = new Person("Hana","Daddy",30);
 
p.introduction("simple");
p.introduction();

//Prototyping : add 
Person.prototype.addAge = function (year) {
	if (year)
		this.age += year;
	else
		this.age +=1;
}
p.addAge(5);
p.introduction();

// new Person inherited class
function GoodPerson(firstname,lastname,age){
	this.fromClass = Person;
	this.fromClass(firstname,lastname,age);
 
	this.characteristic="Good";
	this.doSomethingGood =  function (){
		alert("help others");
	}
}
 
var a = new GoodPerson("Good","Person",20);
a.introduction();