Uncaught TypeError: Cannot set property 'value' of undefined 错误

Question

Uncaught TypeError: Cannot set property 'value' of undefined  提示这个是什么意思？

我的代码是：

var title;
$(document).ready(function(){
    title.value = formartWeek();//这里报错
})
function formartWeek(){
    return currentYear + "年 第 " + currentWeek + " 周";
}

Answer 1

把第一行改成var title = {}