js 处理数组，把指定位置的元素换成最后一个元素并删除最后一个元素
js 处理数组，把指定位置的元素换成最后一个元素并删除最后一个元素var arr = new Array(6);arr[0] = "George";arr[1] = "John";arr[2] = "Thomas";arr[3] = "James";arr[4] = "Adrew";arr[5] = "Martin";arr.splice(2,1,arr...
