Some problems with Weibo 2 input box

Question

Hello teacher, first of all, thank you to all the teachers of php Chinese website. I have two small questions

1. Why is aa() called at the end {}

2. Why tenx. innerHTML=m To unload the external part of {}

3. Why should aa be written at the end

Answer 1

Question 1: JS functions are useless if not called;

Question 2: This is the number of characters we input. It is not loaded externally, but is placed behind the judgment (look at the code carefully) )

Question 3: Same as question 1 Calling function