js的slice方法返回一个新数组(不会修改原素组)
   var arr = ["One","Two","Three"];
   var arrtoo = arr.slice(0);
   arrtoo[1] = "set Map";

   js的concat方法(返回连接数组的副本，不会改变原数组)
   var arr = ["One","Two","Three"];
   var arrtooo = arr.concat();
   arrtooo[1] = "set Map To";

   var cloneObj = function(obj){
     var str, newobj = obj.constructor === Array ? [] : {};
     if(typeof obj !== 'object'){
         return;
     } else if(window.JSON){
         str = JSON.stringify(obj), //序列化对象
         newobj = JSON.parse(str); //还原
     } else {
         for(var i in obj){
             newobj[i] = typeof obj[i] === 'object' ? cloneObj(obj[i]) : obj[i]; 
         }
     }
     return newobj;
 };

var y = $.extend({}, x),          //shallow copy
    z = $.extend(true, {}, x);    //deep copy

   undefined boolean string object(object,null,Array) function

   function People(name){
       this.name = name;
       this.say = function(){
           console.log(this.name)
       }
   }
   var join = new People('join')
   join.name
   join.say()

   class People{
       constructor(name){
           this.name = name;
       }
       say(){
           console.log(this.name)
       }
   }

function sum() {
  var num = arguments[0];
  if(arguments.length === 2) {
    return arguments[0] + arguments[1]
  } else {
    return function(sec) {
       return num + sec;
    }
  }
 
}

function add(x) {
    var sum = x;
    var tmp = function (y) {
        sum = sum + y;
        return tmp;
    };
    tmp.toString = function () {
        return sum;
    };
    return tmp;
}
console.log(add(1)(2)(3));  //6
console.log(add(1)(2)(3)(4));   //10

function add () {
    var args = Array.prototype.slice.call(arguments);
 
    var fn = function () {
        var arg_fn = Array.prototype.slice.call(arguments);
        return add.apply(null, args.concat(arg_fn));
    }
 
    fn.valueOf = function () {
        return args.reduce(function(a, b) {
            return a + b;
        })
    }
 
    return fn;
}
add(1) // 1
add(1,2)(3) //6
add(1)(2)(3)(4)(5) // 15

function UrlSearch() 
{
   var name,value; 
   var str=location.href; //取得整个地址栏
   var num=str.indexOf("?") 
   str=str.substr(num+1); //取得所有参数   stringvar.substr(start [, length ]

   var arr=str.split("&"); //各个参数放到数组里
   for(var i=0;i < arr.length;i++){ 
    num=arr[i].indexOf("="); 
    if(num>0){ 
     name=arr[i].substring(0,num);//第二个参数表示截取到多少位
     value=arr[i].substr(num+1);//第二个参数表示截取多少位
     this[name]=value;
     } 
    } 
} 
var Request=new UrlSearch(); //实例化