SOURCE

// var arr = new Array('南京','长沙','株洲');
// console.log(arr[2]);

// var arr = new Array(10);
// console.log(arr.length);

// 遍历
// var nums=[50,90,20,10];
// for (var i=0;i<nums.length;i++){
//   nums[i] += 10;
// }
// console.log(nums);

//API .join
// var chars = ["H","e","l","l","o"]
// console.log(chars.join(""));

// 拼接 .concat
var arr1 = [90,91,92];
var arr2 = [80,81];
var arr3 = [70,71,72,73];
var arr4 = arr1.concat(9,arr2,"odfmcsdnck",arr3,"d",);

console.log(arr1);
console.log(arr4);