但有一个问题：尝试运行下面的代码，它对某些单元格有效。

But there is a catch: Try running the code below, and it works for some of the cells.

youdao

下面这些练习都有样例代码。不过你最好在看答案之前先自己对每个练习都尝试一下。

There are solutions to these exercises in the next section. You should at least attempt each one before you read the solutions.

youdao

此处尝试的基本小提示，以及相同的代码下面。

Basic fiddle of current attempt here, and identical code below.

youdao