js中如何将有字符串转换为数组,或将数组转换为字符串

var str = "1,2,3,4,5";

var array = str.split(",");//逗号是分隔符

返回  [1,2,3,4,5]

var a = [1,2,3,4,5];  //定义数组

var s = a.join("，");  //指定分隔符

console.log(s);  //返回字符串“1，2，3，4，5”