How to detect character set encoding?

Question

For example, chinese text(GB2312) is pasted into a text box(or text area) of a html page and the form is posted. At the server side, is there any means by which this character set gets detected?

How would this detection behave if texts belonging to different character sets are pasted in a text box?

Answer 1

The web browser should send up a content type including encoding when it posts the data.

I find it helpful to think of text as "just text" (without any particular encoding) until an encoding is required. So the browser shouldn't care what encoding (if any) was used to originally produce the text (e.g. if it was copied and pasted from a file, the file's encoding is irrelevant). It decides what encoding to use when posting it to the server, obviously making sure that it's an encoding which covers all the characters it needs to send.

Answer 2

if you use php on the server, you can use mb_detect_encoding

Answer 3

You need to tell the browser what encoding to use by adding an accept-charset="UTF-8" (or similar) attribute to the form. Apparently this defaults to the character set of the page, but I wouldn't count on that. The browser won't tell you what encoding it used when it submits the form, so you need to assume it used the one you told it to.