javascript - Use form to jump to the page, but it is very slow. How to add a Loading?

Question

Now the front and back ends of the project are not separated. The page has a form to jump, but the query is very slow. Now I have temporarily added a loading effect, which is displayed when the button is clicked, but the loading will not disappear when clicking return in Apple WeChat. I It is estimated that js will not be executed when returning. How to make this loading disappear before the page jumps? The page is as follows:

Answer 1

It can be made into ajax, which is easier to handle. ps: You need to pay attention to the problem of slow query. During development, query is relatively slow, but when it is put into use, it will be okay

Answer 2

Just use layer