Javascript-3 web development team, how to cooperate in interaction?

I write the front-end and the other two write the back-end. My problem now is: I can write all the pages on the front end, write interaction effects, and use ajax. But the key is that I can't write the static page and give it to the backend, so that they have been idle for a long time in the middle. How do I fill in the idle time? Thank you for your advice. Javascriptphphtml

I write the front-end and the other two write the back-end.
My current problem is:
I can write all the front-end pages, write interaction effects, and use ajax. But the key is that I can't write the static page and give it to the backend, so that they have been idle for a long time in the middle. How do I fill in the idle time?

Thank you for your advice.