JavaScript 中字符串转为Json对象出错的解决

var text = '{a:"aa\r\nb\r\nb",b:"33"}';
var json = eval("(" + text + ")");// 报错：未结束的字符串常量

//正确
while (text.indexOf("\r") >= 0) {
                text = text.replace("\r", "\\r");
                text = text.replace("\n", "\\n");
            }
 var json = eval("(" + text + ")");