My app is showing error when I'm sending form data via AJAX

Hey Guyz!
I’m developing a social app using ionic. I’m sending form data to the database with AJAX. Though its working well but still its showing the following Type Script Error:
Argument of type ‘HTMLElement’ is not assignable to parameter of type ‘HTMLFormElement’. Property ‘acceptCharset’ is missing in type ‘HTMLElement’.
Any Suggestion?

What are you doing with any of that? Smells very unidiomatic.

Because its working fine and its pretty easy. Do you have any suggestions about that?