How to use formData option{}

[mthohirin]

i added enctype="multipart/form-data" to <form> element, but Pjax still dont want read my fileinput element <input type="file" />

i also added "form[action]" into Pjax.
Pjax({ elements: "form[action]" })

when i click submit, i got this error
Pjax switch fail: TypeError: Cannot read properti 'match' of null

maybe any suggestion for my case? thanks