pop：删除原数组最后一项，并返回删除元素的值；如果数组为空则返回undefined
var a = [1,2,3,4,5];
var b = a.pop();//a：[1,2,3,4] b：5
console.log(a, b);
push：将参数添加到原数组末尾，并返回数组的长度
var a = [1,2,3,4,5];
var b = a.push(6,7); //a：[1,2,3,4,5,6,7] b：7
concat: 返回一个新数组,是将参数添加到原数组中构成的
var a = [1,2,3,4,5];
var b = a.concat(6,7);//a：[1,2,3,4,5] b：[1,2,3,4,5,6,7]
splice(start,deleteCount,val1,val2,...)：从start位置开始删除deleteCount项，并从该位置起插入val1,val2,...
var a = [1,2,3,4,5];
var b = a.splice(2,2,7,8,9);
console.log(a, b);
var b = a.splice(0,1); //同shift
a.splice(0,0,-2,-1);
var b = a.length; //同unshift
var b = a.splice(a.length-1,1); //同pop
console.log(b);
a.splice(a.length,0,6,7);
var b = a.length; //同push
split() 用于把一个字符串分割成字符串数组,数组一般是字符串处理比较常用的处理方法
var a = 'abcd';
var b = a.split('');
reverse: 将数组反序
var a = [1,2,3,4,5];
var b = a.reverse();//a：[5,4,3,2,1] b：[5,4,3,2,1]
sort(orderfunction)：按指定的参数对数组进行排序
var a = [1,2,3,4,5];
var b = a.sort(); //a：[1,2,3,4,5] b：[1,2,3,4,5]
join将数组的元素组起一个字符串，以separator为分隔符，省略的话则用默认用逗号为分隔符
var a = [1,2,3,4,5];
var a = [1,2,3,4,5];
var b = a.join('');//a：[1,2,3,4,5] b："12345"
