第二次理解json

// js对象和json 的区别 ???var friend ={ ???????firstname:‘zhang‘, ???????lastname:‘cl‘, ???????address:null, ???????// address:‘‘, ???????// address:undefined, ???}; ???// ????var str = ‘{"name":"alan"}‘; ???// json 格式对象 ???var json ={ ???????"name":"alan", ???????"age":"23", ???????"gender":"female", ???}; ???// json 格式数组 ???var arr =[ ???????{ ???????"name":"alan", ???????"age":"23", ???????"gender":"female", ???}, ???{ ???????"name":"kitty", ???????"age":"23", ???????"gender":"female", ???}, ???{ ???????"name":"tom", ???????"age":"23", ???????"gender":"male", ???} ???] ???var json2 = JSON.parse(str); ???// json 格式的对象 ???// ????var str = ?JSON.stringify(friend); ???var str2 = ‘{"firstname":"zhang","lastname":"cl","address":null}‘; ???var json3 = {"firstname":"zhang","lastname":"cl","address":null} ???// console.log(str); ???console.log(typeof(json3));