encode/decode base64 with JS

Encoding to base64 is done with the btoa command

btoa("This is a test.")
> "VGhpcyBpcyBhIHRlc3Qu"

To decode a base64 encoded string, use the atob command

atob("VGhpcyBpcyBhIHRlc3Qu")
> "This is a test."

serialize Form

Sử dụng formdata constructor để convert form, FormData, array.from(). Kết hợp window.encodeURIComponent() để encode từng value trong form.

promise + gì