字符串=>数组
var B = '9876';
var BArr = B.split('');//以什么来分割
console.log('原字符串:'+B);
console.log('转后是否是数组类型:'+Array.isArray(BArr))
console.log(BArr);
数组=>字符串
var A = [1,2,3,4,5];
var AString =A.toString();//以逗号隔开的字符串
console.log('原数组:'+A)
console.log('倒序原数组:'+A.reverse())
console.log('转后类型:'+typeof(AString))
console.log('转换后字符串:'+AString.replace(/,/g,''))//去除逗号
var B =[1,2,3,4];
console.log(B.join(""));//1234