无法使用ajax / javascript将文件上传到perl脚本

I have a form that takes a sinlge file image for upload to a perl script which uses binmode to read and save. The perl script does not seem to be getting the file stream (filesize ends up 0 bytes in size). I'm not sure if I'm passing/using the right name/ref from the html input into the javascript formdata.append. I'm avoiding jquery and xhr version 2 solutions for the time being. I'm determined to make this work if possible.I have a form that takes a sinlge file image fo