eval()解析json以及js中js数组、对象与json之间的转换

http://www.cnblogs.com/myjavawork/articles/1979279.html

https://www.cnblogs.com/coder-economy/p/6203864.html

var a= '{"session_key":"bsm+VwaGnpeTe9mRC2drdQ==","expires_in":7200,"openid":"oY8Ly0JzGKDvM9C7KwSjAIBt-8fM","unionid":"oB2ANwOMEJ9cPM2qKV3Zz1_R4zuM"}';
var a = eval("(" + a + ")");
console.log(a.unionid);
console.log(typeof(eval("{}")));//undefined
console.log(typeof(eval("({})")));//object