js中数组转字符串，json字符串转js对象

1.js中数组转字符串
var arr = ["a","b","c"];

alert(arr.join(","));//输出a,b,c 相当于arr.toString();

alert(arr.join("");//输出abc

alert(arr.join());//什么都不输入，就等于用逗号将他们分割arr.join(",");也相当于arr.toString();输出a,b,c

alert(arr.join('|'));这段代码表示没试过

2.json字符串转js对象三种方式
var json = eval('(' + str + ')');
var json = (new Function("return " + str))(); 
var json = JSON.parse(str);