//关于数组
			//创建数组和存取数组
			var arr1=new Array();
			arr1=[1,2,3];
			var arr2=[];
			var arr3=["吴琼",2,"str",{name:"吴琼",age:28}];
			arr2[0]=1;
			arr1[3]=4;
			arr1[arr1.length]=5;
			console.log(arr1);
			console.log(arr1[arr1.length-1]);//最后一项的索引始终是length-1
			console.log(arr2);
			console.log(arr2[0]);
			console.log(arr3);
			console.log(arr3[3].name);
			if(arr1 instanceof Array){
				console.log("arr1 是数组");
			}else{
				console.log("arr1 不是数组");
			}
			if(Array.isArray(arr2)){
				console.log("arr2 是数组");
			}else{
				console.log("arr2 不是数组");
			};
			console.log(arr1.toString());
			console.log(arr1.toLocaleString());
			console.log(arr1.valueOf());
			console.log(arr1.join("/"));
			//alert(arr1.join());  //后台自动调用arr1.toString();
			console.log(arr1.push(6,7,"8","pop（）这个项"));//返回新数组的长度
			console.log(arr1);
			console.log( arr1.pop());  //返回取出来的项
			
			console.log(arr1);
			var arr4=new Array();
			console.log(arr4.unshift(1,2));  //返回新数组的长度 2	
			console.log(arr4);
			console.log(arr4.shift());
			console.log(arr4);
			console.log(typeof arr4.shift());
			console.log(arr4);
			var arr5=[0,5,15,10,20,"a","b",30];
			console.log(arr5.reverse()); //改变了原数组 
			console.log(arr5.sort());    //[0,10,15,20,5]  转变为字符串比较后的排序结果
			console.log(arr5.sort(function(a,b){return a>b}));
			var colors=[1,2,3];
			var colors2=colors.concat(4,[5,6]);
			console.log(colors2);  //返回一个新数组
			var colors3=colors2.slice(1);    
			var colors4=colors2.slice(1,5); 
			var colors5=colors2.slice(1,colors2.length-1);
			console.log(colors3);
			console.log(colors4);
			console.log(colors5);
			var cars =["奔驰","宝马","奥迪"];
			var cars1 =cars.splice(0,1);   //删除奔驰
			console.log(cars);
			console.log(cars1);
			var cars2 = cars.splice(0,1,"奔驰","别克");//替换宝马
			console.log(cars);
			console.log(cars2);
			var cars3 = cars.splice(2,0,"大众"); //插入大众
			console.log(cars);
			console.log(cars3);
			var age={name:"wq"};
			var age1=[{name:"wq"},2,{a:2,b:3}];
			if(!Array.indexOf){
             		Array.prototype.indexOf = function(el){
             		    for (var i=0,n=this.length; i<n; i++){
             			    if (this[i] === el){
             				    return i;
             		        }
             		    }
                        return -1;
                    }  
                }
			console.log(age1.indexOf({name:"wq"}));  //-1
			console.log(age1.indexOf(2));   //1
			console.log(arr1.indexOf({a:2,b:3}));//-1
			
			var iter=[1,2,3,4,3,2,1];
			var everyResult = iter.every(function(item,index,array){
				return item > 2;
			});
			console.log(everyResult);
			var someResult = iter.some(function(item,index,array){
				return item > 2;
			});
			console.log(someResult);
			var filterResult = iter.filter(function(item,index,array){
				return item > 2;
			});
			console.log(filterResult);
			var mapResult = iter.map(function(item,index,array){
				return item > 2;
			});
			console.log(mapResult);   //这个返回一个由布尔值组成的数组
			var mapResult1 = iter.map(function(item,index,array){
				return item * 2;
			});
			console.log(mapResult1);
			iter.forEach(function(item,index,array){
				//这里执行一些代码
				if(array[index]>2){
					console.log(item);
				}else{
					
				}
			});
			console.log(iter);
			var sum=iter.reduce(function(pre,cur,index,array){
				return pre + cur;
			});
			console.log(sum);