show() is invalid after ajax success

Question

The console can print login success and 222, but the element always flashes on the page and disappears. What's going on?

Answer 1

When there is a button tag in the form, and the form is submitted asynchronously using ajax, the page will be refreshed
Reason: When the button exists, the form will be submitted again, so the page is refreshed
Solution: Just replace the button tag with an a tag

Answer 2

Either your selector did not select the right one, or other Js is interfering at the same time

Answer 3

Probably covered. You can find out by turning on debugging and looking at the style of the right element.