Im new to web development, and I have setup my postman and it makes successful POST calls to the appropriate link, I am trying to replicate this in javascript, but I wasn't sure what I would use, do I use fetch, $.ajax or XMLHttpRequest. Postman is sending a Body aswell with values one of them being an uploaded file, and some header values one of the header values being Content-Type: "multipart/form-data", I assume I should be sending them as well, but I am not sure what the syntax or format would be. Currently I keep getting error 400 or sometimes error 412.