javascript-how to dynamically increase the order of elements?

javascriptphp Front-end jquery

     
   
       JQuery Test        Click
   
   
   

Click Add Li, click Delete to update the Li inside the number and attribute ID, but the increase or in the original order to increase, how to change it?
Cases:
1------Delete
2------Delete
3------Delete
4------Delete
5------Delete
6------Delete
7------Delete
8------Delete
9------Delete
Delete------

Click Delete to change the number dynamically:
1------Delete
2------Delete
3------Delete
4------Delete
5------Delete
6------Delete
7------Delete

Then click Add:

1------Delete
2------Delete
3------Delete
4------Delete
5------Delete
6------Delete
7------Delete
------Delete
Delete------
Delete------

Increased because it is n++ determined, so there is no dynamic change

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