Js cc.sys.localStorage.getItem总是失败 【已解决】

Cocos2d-x JavaScript
#1

在android手机中是获取到空值
并且我有
cc.log(this.m_Difficulty);
if (this.m_Difficulty == null)
this.m_Difficulty = 0;
else
this.m_Difficulty = parseInt(this.m_Difficulty);
cc.log(this.m_Difficulty);

#2

打印的是JS: NaN
Nan是js的空值 在cocos怎么写。。。

#3

卧槽 这不科学 必须要这样写 HTML 跟binding是不一样的空值
this.m_Difficulty = cc.sys.localStorage.getItem(KEY_DIFFICULTY);
cc.log(this.m_Difficulty);

    if (this.m_Difficulty )
        this.m_Difficulty = parseInt(this.m_Difficulty);
    else
        this.m_Difficulty = 0;
    cc.log(this.m_Difficulty);
#4

怎么解决的？？？说一下！