Specific code can look at the pictures I sent you a, these are I see public class learning, code exactly like the one with the teacher, but the teacher didn't complain, my error, and a great god help have a look at the wrong where how to fix it?

CodePudding user response:

Ul: first, the child is the first child of the parent element matched elements ul, but your ul is not its parent element of the first child, so can't match,
Should be changed to ul: first - of - type

CodePudding user response:

The teacher's code & lt; Div id="prev" & gt;