pop()方法从数组中删除最后一个元素并返回该元素。
array.pop();
从数组中返回已删除的元素。
var numbers = [1, 4, 9];
var element = numbers.pop();
console.log("element is : " + element );
var element = numbers.pop();
console.log("element is : " + element );
element is : 9
element is : 4