Resolution: div failed to get keyboard event

Today to div When adding key monitoring, I found that , I can't get the monitoring event

Looking up the data, I found , original html Elements are also categorized by focus , Because the keyboard is different from the mouse ：

（1） The mouse can be moved , Select the triggered element

（2） The keyboard doesn't know which element to pass key information to , It is also not possible to move the mouse inside the element every time you type , Then enter the keyboard ........

But because of the concept of focus , Generally, there is at most one focus , Then the keyboard can output according to the focus element .

We can use the element's own tabindex The attribute is div Add permission to have focus .

tabindex="-1"      Element has focus permission , The selection will not show , It won't be tab Select... When switching .

tabindex="1"      Element has focus permission , The selection will show , Will be tab Toggle selected

tab When switching focus elements , Will be based on tabindex The value size determines the order , The smaller the value. , The higher the priority , The sooner you are chosen , The bigger the value is. , The later it is selected .

After adding the attribute , You'll find that ,div You can receive keyboard events