/**
* The Mobile Common Object
* @class Common
* @static
*/
var SN = SN || {};
SN.Common = (function(){
    'use strict';

    var _getUrlParams = function(ulr){
			//...
		}

		//...

		return {
			/**
			* Get the URL params
			* @params {string} url request url
			* @returns {Array} url params array
			* @method _getUrlParams
			*/
			getUrlParams: function(url){_getUrlParams(url);}
		}

})();

//调用
SN.Common.getUrlParams('xxxx');

function test() {
    return //javascript 编译器认为语句结束，直接返回
        {
           name: 'foobar'
        };
}

function test() {
    return {
        name: 'foobar'
    };
}

'1' == 1 // true
'' == 0 // true
false == '0' // true
' \t\r\n ' == 0 // true

'1' === 1 // false
'' === 0 // false
false === '0' // false
' \t\r\n ' === 0 // false

var num = new Number(8);
var str = new String('foobar');
console.log(typeof num); //object
console.log(typeof str); //object

//num和str的valueOf返回的是object,如果此时用这种方式比较，就会出问题
var str2 = 'foobar';
str2.replace('foobar', 'hello, world') // str2先转化为内建包装对象

for (var prop in obj) {
    if (d.hasOwnProperty(prop)) {
        console.log( prop + ": " + obj[prop] );
    }
}

var obj = { name: "foobar"},
name = "helloworld";

with (obj) {
    console.log(name); // 如果变量和对象属性同名，使用变量 => helloworld
    occupation = "IT"; // 对象无法带着这个属性出去，但是它自己可以出去
}

console.log(obj.occupation); // undefined;
console.log(occupation); // IT

eval('console.log("Hello, World")'); //可以执行javascrtip文本

parseInt("10"); // 10
parseInt("010"); // 8， 发现0开头，认为要转成8进制
parseInt(val, 10);

var arr = [1,2,3,4,5,6,7,8,9,10],
    len = arr.length,
    index = len;

while(index--) { // 0为false, 不要比较，这样效率会更好一些
    console.log(arr[index]);
}

function _name(person) {
	  //...
}
//set ? -> get ? -> modify? -> delete? -> ...

function _getName(person) {
    //...
}

var a = function() {
    var numArr = [1,2,3];
    return function() {
        return numArr;
    };
}();

var authorized = false,
    active;

if(authorized) {
    active = true;
} else {
    active = false;
}

var active = authorized ? true : false;

//执行函数
authorized ? function(){
                 console.log('user is active...');
             }()
           : function(){
                 console.log('user is not active...');
           }();

//多个表达式
var a,b;
authorized ? (a = 1, b = 2) : (a = b = 0);

//嵌套
var c;
authorized ? (a = 1, b = 2) : authorized ? c = 3 : c = 0;

var class = {
    _addMember: function(member){
        this.members = this.members ? this.members : [];
        this.members.push(member);
    }
};

=>

var class = {
    _addMember: function(member){
        this.members = this.members || [];
        this.members.push(member);
    }
};

function findKindVal(kind){
    if(kind == 'a') {
        return 0;
    } else if(kind == 'b') {
        return 1;
    } else if(kind == 'c') {
        return 2;
    }...
}

=>

function findKindVal(kind) {
    switch(kind) {
        case 'a':
            return 0;
        case 'b':
            return 1;
        case 'c':
            return 2;
        case 'd':
        case 'e':
            return 3;
        default:
            return '-1';
    }
}

var list = document.getElementById('book_list');
for(var i = 0; i < 10; i++) {
    var element = document.createElement('li');
    element.appendChild(document.createTextNode('book_' + i));
    list.appendChild(element);
}

=>

var list = document.getElementById('book_list'),
    fragment = document.createDocumentFragment(),
		element;

for(var i = 0; i < 10; i++) {
	  element = document.createElement('li');
    element.appendChild(document.createTextNode('book_' + i));
    fragment.appendChild(element);
}

list.appendChild(fragment);

var a = 1;
var b = 2;
var foo = 'bar';

=>

var a = 1,
    b = 2,
    foo = 'bar';

for(var i = 0; i < 10; i++) {
    var element = document.createElement('li');
}

=>

var element;
for(var i = 0; i < 10; i++) {
    element = document.createElement('li');
}

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

for(var i = 0; i < len; i++) {
    result += strs[i];
}

=>

var result = strs.join('');

i.toString() // '' + i

var obj = {
    a: xxx,
    b: xxx
};
List.push(obj); //obj只用到一次

if (!list || (list && !list.length)) {

//=>

if (!list || !list.length) { //不存在或者存在但是为空

if (level == 0) {

=>

if (!level) {

(new Date()).getTime()

=>

+new Date()

if (!checkbox.checked) {
    checkbox.checked = true;
} else {
    checkbox.checked = false;
}

=>

checkbox.checked = (!checkbox.checked) ? true : false;

if (selectedValue) {
    $input.val(selectedValue);
} else {
    $input.val("");
}

=>

$input.val(selectedValue || "");

inputs.length && inputs.forEach(function (input) {

=>

inputs.forEach(function (input) {

course.showTips("请输入正确的手机号！");

SNError.PHONE_FORMATTER

!(function(global){
    var SNError = {
        PHONE_FORMATTER: '请输入正确的手机号！'
		}
global.SNError = SNError;
})(this);

//后面只需要维护这个SNError即可，同时也会减少js文件的大小

//实例化后每个对象占用内存会随着方法而线性扩展
(function(){
    function A () {
        this.name = 'foobar';
        this.greeting = function(){
            console.log(this.name)
        }
    }

    var a = new A();
    a.greeting();
    console.log(a.hasOwnProperty('greeting'))
})();

var _this = this;
var db = this.getSessionStorage();
var _activeCode = URL_PARAM["xxx"];

=>

var _this = this,
    db = this.getSessionStorage(),
    _activeCode = URL_PARAM["xxx"];

me.removeClass("focus");
me.addClass("gray");

=> me.removeClass("xxxx").addClass("xxx")

//除完后如果是小数？
parseInt((len - maxlimit + 1) / 2)

=>

parseInt((len - maxlimit + 1) / 2, 10)

location.href = "./error.html?errorMsg=" + xxx.SYSTEM_ERROR_MSG();

=>

location.href = "./error.html?errorMsg=" + encodeURIComponent(xxx.SYSTEM_ERROR_MSG());

$("#xxx").find(".xxx").length || 0

=》

$("#xxx").find(".xxx").length

//变量表达式重复使用到，没有缓存到变量中。

xxx.getXXXX();

=>

var state = xxx.getXXXX();

window.moduleName.moduleMethod

=>

moduleName.moduleMethod

$obj.css("visibility","hidden");

=>

$obj.show();

//条件会互斥的话，只会走一个分支
if(_variableName == "xxxxx"){
    //...
}
if(_variableName == "xxxxx"){
    //...
}

=> if ... else if ... 或者switch (条件多的话，优先考虑)

obj["a"] = a;
obj["b"] = b;
obj["c"] = c;
obj["c"]= d;

=>

obj = $.extend(obj, {
   a: xxxx
   //...

if(....) {
    str = '计算获取'
    return str
}else {
    return '';
}

=>

var str = '';
if(....) {
    str = '计算获取'
    return str;
}

//字面量声明

var arr = new Array();

=>

var arr = [];

$("#xxxx").unbind("click");
$("#xxxx").click(function(){
    //...
});

=>

$("#xxxx").unbind("click").bind('click',function() {
    //...
});