Answer 1

This example shows automatic slider:

https://code.sololearn.com/WUXX65sU8ciG/?ref=app

Answer 2

people are more likely to test your code if you put your ***complete*** code as s minimal working example on sololearn playground:

Go to Code section, click +, select the programming language, insert your code, save.
Come back to the thread, click +, Insert Code, sort for My Code Bits, select your code.