What is the '-' in multipart/form-data?

Question

I want to ask a question about the multipart/form data. I find the http header of multipart post and the Content-Type: multipart/form-data; boundary=-----...---boundaryNumbe

Answer 1

The number of dashes depends on how many you want there. It can be zero, if you like -- it's just that more dashes makes the boundary more obvious.

The boundary consists of a line containing two dashes plus everything after "boundary=". So if your header said boundary=ABC, the boundary looks like

--ABC