"use strict"

var o = new Object();

"23" < "3"   // true

NaN == NaN  // false
NaN === NaN  // false
NaN > NaN  // false
NaN < NaN  // false

"55" == 55  // true
"55" === 55  // false

variable = boolean_expression ? true_value : false_value;

for (var i = 0; i < 10; i++) {
	var j = 1;
}
console.log(i, j);  // 10 1

for (property in expression) {
  ...
}

var num = 0;

outermost:
for (var i = 0; i < 10; i++) {
	for (var j = 0; j < 10; j++) {
		if (i == 5 && j ==5) {
			break outermost;
		}
		num++;
	}
}

console.log(num);  // 55

function example(name, age) {
	console.log('arguments:', arguments);
	console.log('name:', name, 'age:', age);
	name = 'DIYgod';
	console.log(arguments[0]);
}
example('Anotherhome', '556', 'www.anotherhome.net');

// arguments: ["Anotherhome", "556", "www.anotherhome.net"]
// name: Anotherhome age: 556
// DIYgod

var o1 = {};
var o2 = o1;
o1.name = 'DIYgod';
console.log(o2.name);  // DIYgod

var n1 = 1;
var n2 = n1;
n1 = 2;
console.log(n2);  // 1

function setName(o) {
	o.name = 'DIYgod';
	o = {};
	o.name = 'Anotherhome';
}

var p = {};
setName(p);
console.log(p.name);  // DIYgod

// new 操作符法
var o1 = new Object();
o1.name = 'DIYgod';
o1.age = 20;

// 对象字面量表示法
var o1 = {
  name: 'DIYgod',
  age: 20
}

// 点表示法
console.log(o.name);

// 方括号表示法
console.log(o['name']);

var n = 'name';
console.log(o[n]);

console.log(o['first name'];

var a1 = new Array();
var a2 = new Array(20);
var a3 = new Array('red', 'blue', 'green');

var a4 = [];
var a5 = ['red', 'blue', 'green'];

var a = ['a', 'b'];
a[a.length] = 'c';

var a = [0, 1, 15, 10, 5];
a.sort();
console.log(a)  // [0, 1, 10, 15, 5]

function compare(value1, value2) {
	return value1 - value2;
}
a.sort(compare);
console.log(a)  // [0, 1, 5, 10, 15]

var a1 = ['red', 'green', 'blue'];
var a2 = a1.concat('yellow', ['black', 'brown']);
console.log(a2)  // ["red", "green", "blue", "yellow", "black", "brown"]

var a = ["red", "green", "blue", "yellow", "black", "brown"];
console.log(a.slice(1), a.slice(1, 4))  // ["green", "blue", "yellow", "black", "brown"] ["green", "blue", "yellow"]

var a = ["red", "green", "blue", "yellow", "black", "brown"];
console.log(a.splice(2, 1), a);  // 删除项; ["blue"] ["red", "green", "yellow", "black", "brown"]
console.log(a.splice(1, 0, 'yellow', 'orange'), a);  // 插入项; [] ["red", "yellow", "orange", "green", "yellow", "black", "brown"]
console.log(a.splice(1, 1, 'red', 'purple'), a);  // 替换项; ["yellow"] ["red", "red", "purple", "orange", "green", "yellow", "black", "brown"]

var a = ["red", "purple", "orange", "green", "red", "yellow", "black", "brown"];
console.log(a.indexOf('red'));  // 0
console.log(a.lastIndexOf('red'));  // 4
console.log(a.indexOf('red', 1));  // 4
console.log(a.lastIndexOf('red', 1));  // 0

var a = [1, 2, 3, 4, 5, 4, 3, 2, 1];

var everyResult = a.every(function (item, index, array) {
	return (item > 2);
});
console.log(everyResult);  // false

var someResult = a.some(function (item, index, array) {
	return (item > 2);
});
console.log(someResult);  // true

var filterResult = a.filter(function (item, index, array) {
	return (item > 2);
});
console.log(filterResult);  // [3, 4, 5, 4, 3]

var mapResult = a.map(function (item, index, array) {
	return (item * 2);
});
console.log(mapResult);  // [2, 4, 6, 8, 10, 8, 6, 4, 2]

var forEachResult = a.forEach(function (item, index, array) {
	console.log(item);
});
console.log(forEachResult);  // undefined

var a = [1, 2, 3, 2, 1];

var sum1 = a.reduce(function (prev, cur, index, array) {
	console.log(index);  // 1 2 3 4
	return prev + cur;
});
console.log(sum1);  // 9

var sum2 = a.reduceRight(function (prev, cur, index, array) {
	console.log(index);  // 3 2 1 0
	return prev + cur;
});
console.log(sum2);  // 9

var d1 = new Date();

var d2 = new Date(2015, 2, 5, 17, 55, 55);  // 2015年3月5日下午5点55分55秒

var start = Date.now();
doSomething();
var stop = Date.now();
var result = stop - start;

var d2 = new Date(2015, 2, 5, 17, 55, 55);
d2.toString();  // "Thu Mar 05 2015 17:55:55 GMT+0800 (CST)"
d2.toDateString();  // "Thu Mar 05 2015"
d2.toTimeString();  // "17:55:55 GMT+0800 (CST)"
d2.toLocaleString();  // "2015/3/5 下午5:55:55"
d2.toLocaleDateString();  // "2015/3/5"
d2.toLocaleTimeString();  // "下午5:55:55"

var exp1 = / pattern / flags
var exp2 = new RegExp('pattern', 'flags');

var text = "I'm DIYgod, and this is Anotherhome";
var pattern = /and( this( is)?)?/gi;
var matches = pattern.exec(text);
console.log(matches.index);  // 12
console.log(matches.input);  // I'm DIYgod, and this is Anotherhome
console.log(matches[0]);  // and this is
console.log(matches[1]);  //  this is
console.log(matches[2]);  //  is

var text = "I'm DIYgod, and this is Anotherhome";
var pattern = /DIYgod/;
var matches = pattern.test(text);
console.log(matches);  // true

// 使用函数声明语法
function f1 (n1, n2) {
	return n1 + n2;
}

// 使用函数表达式
var f2 = function (n1, n2) {
	return n1 + n2;
};

// 使用构造函数，不推荐
var f3 = new Function('n1', 'n2', 'return n1 + n2');

function f1 (n1, n2) {
	return n1 + n2;
}
var f2 = f1;
f1 = null;
console.log(f2(1, 1));  // 2

console.log(f1(1, 1));  // 2
function f1 (n1, n2) {
	return n1 + n2;
}

console.log(f2(1, 1));  // Uncaught TypeError: f2 is not a function
var f2 = function(n1, n2) {
	return n1 + n2;
}

// 明显第二种写法更好一些

function factorial1 (num) {
	if (num <= 1) {
		return 1;
	}
	else {
		return num * factorial1(num - 1);
	}
}

function factorial2 (num) {
	if (num <= 1) {
		return 1;
	}
	else {
		return num * arguments.callee(num - 1);
	}
}

function outer() {
	inner();
}
function inner() {
	console.log(arguments.callee.caller);  // function outer()...
}
outer();

function f (n1, n2) {
	return n1 + n2;
}
console.log(f.length);  // 2

window.color = 'red';
var o = {
	color: 'blue'
};

function sayColor (n1, n2) {
	console.log(this.color);
	return n1 + n2;
}

sayColor(1, 1);  // red
o.sayColor = sayColor;
o.sayColor();  // blue

// 使用call和apply可以消除对象与方法的耦合关系
sayColor.call(window, 1, 1);  // red
sayColor.call(o, 1, 1);  // blue

sayColor.apply(window, [1, 1]);  // red
sayColor.apply(o, [1, 1]);  // blue

function createPerson(name, age, job) {
	var o = new Object();
	o.name = name;
	o.age = age;
	o.job = job;
	o.sayName = function () {
		console.log(this.name);
	}
	return o;
}
var p1 = createPerson('DIYgod', 20, 'Software Engineer');
var p2 = createPerson('Anotherhome', 2, 'Website');

function Person(name, age, job) {
	this.name = name;
	this.age = age;
	this.job = job;
	this.sayName = function () {
		console.log(this.name);
	}
}
var p1 = new Person('DIYgod', 20, 'Software Engineer');
var p2 = new Person('Anotherhome', 2, 'Website');

// p1 p2 分别保存着 Person 的一个不同的实例，这两个对象都有一个 constructor 属性，该属性指向Person
console.log(p1.constructor);  // function Person(name, age, job) {...

console.log(p1 instanceof Object);  // true
console.log(p1 instanceof Person);  // true

console.log(p1.sayName === p2.sayName);  // false

// 组合使用构造函数模式与原型模式
function Person(name, age, job) {
	this.name = name;
	this.age = age;
	this.job = job;
}
Person.prototype.sayName = function () {
	console.log(this.name);
}
var p1 = new Person('DIYgod', 20, 'Software Engineer');
var p2 = new Person('Anotherhome', 2, 'Website');

console.log(p1.sayName === p2.sayName);  // true

// in操作符会在通过对象能够访问到属性时返回true
console.log('name' in p1);  // true

// 枚举属性
for (var prop in p1) {
	console.log(prop);  // name age job sayName
}

function Person() {
}
Person.prototype = {
	constructor: Person,  // 这里重写了prototype，不再默认有constructor属性
	name: 'DIYgod',
	age: 20
};

function SuperType(name) {
	this.name = name;
	this.color = ['red', 'blue', 'green'];
}
SuperType.prototype.sayName = function () {
	console.log(this.name);
}

function SubType(name, age) {
	SuperType.call(this, name);  // 借用构造函数
	this.age = age;
}
SubType.prototype = new SuperType();  // 原型链
SubType.prototype.constructor = SubType;  // construcotr在上一句中被重写
SubType.prototype.sayAge = function () {
	console.log(this.age);
}

var instance = new SubType('DIYgod', 20);
instance.sayName();  // DIYgod
instance.sayAge();  // 20

console.log(instance instanceof SuperType);  // true
console.log(SuperType.prototype.isPrototypeOf(instance));  // true

function outer () {
	var name = 'DIYgod';
	return function () {
		console.log(name);
	}
}
var inner = outer();
inner();  // DIYgod
inner = null;  // 解除对outer内部的匿名函数的引用，以便释放内存

function createFunction () {
	var result = [];
	for (var i = 0; i < 10; i++) {
		result[i] = function () {
			return i;
		}
	}
	return result;
}
console.log(createFunction()[0]());  // 10
console.log(createFunction()[1]());  // 10
// 返回的都是同一个变量i

var name = 'The Window';
var object = {
	name: 'My Object',
	getNameFunc: function () {
		return function () {
			return this.name;
		}
	}
}
console.log(object.getNameFunc()());  // The Window

(function () {
	var i = 9;
	console.log(i);  // 9
})();
console.log(i);  // Uncaught ReferenceError: i is not defined

function MyObject() {
	// 私有变量和私有函数
	var privateVariable = 'DIYgod';
	function privateFunction() {
		console.log('lalala');
	}

	// 特权方法
	this.publicMethod = function () {
		console.log(privateVariable);
		privateFunction();
	};
}
var o = new MyObject();
o.publicMethod();  // DIYgod lalala
o.privateFunction();  // Uncaught TypeError: o.privateFunction is not a function

<input type="button" value="Click Me" onclick="alert(value)">

<form method="post">
    <input type="text" name="username" value="">
    <input type="button" value="Echo username" onclick="alert(username.value)">
</form>

// 绑定事件处理程序
var btn = document.getElementById('myButton');
btn.onclick = function () {
	console.log(this.id);    // myButton
}

// 删除事件处理程序
btn.onclick = null;

var btn = document.getElementById('myButton');
btn.attachEvent('onclick', function () {
	console.log(this === window);    // myButton
});

var xhr = new XMLHttpRequest();
xhr.onreadystatechange = function () {
	if (xhr.readState === 4) {
		if (xhr.status >= 200 && xhr.status < 300 || xhr.status === 304) {
			console.log(xhr.responseText);
		}
		else {
			console.log('Request was unsuccessful: ' + xhr.status);
		}
	}
};
xhr.open('get', 'example.php', true);
xhr.send(null);

var img = new Image();
img.onload = img.onerror = function () {
	console.log('Done!');
};
img.src = 'http://api.hitokoto.us/rand?encode=jsc';

function myCallBack (data) {
	console.log(data.hitokoto);  // 像平常的你一样引发奇迹吧-
}
var script = document.createElement('script');
script.src = 'http://api.hitokoto.us/rand?encode=jsc&fun=myCallBack';  // 返回一个包含在函数调用中的JSON，调用了myCallBack函数：myCallBack({"hitokoto":"...","author":"...",....});
document.body.insertBefore(script, document.body.firstChild);