http://blog.csdn.net/u011277123/article/details/53055479
有三种方法:
var str = '{"name":"小明","age":18}';
将字符串转化json对象:
1. var json = JSON.parse(str);
2. var json = eval("(" + str + ")");
3. var json = (new Function("return " + str))();
注意应该是单引号在外,双引号在内,不能反