PHP: Current encoding used to send data to the browser

Question

How can I know what encoding will be used by PHP when sending data to the browser? I.e. with the Cotent-Type header, for instance: iso-8859-1.

Answer 1

You can set your own with header('Content-type: xxx/yyy');, but I believe that text/html is sent by default.

Answer 2

AFAIK, PHP sends strings bytewise. that is, if your variables hold UTF-8, it will send UTF-8. if you have iso-8859-1, it will send that too. if you mix them, it won't be pretty.

Answer 3

You can use the header() solution that William suggested, however if you are running Apache, and the Apache config is using a default charset, that will win everytime (Internet Explorer will go crazy) See: AddDefaultCharset

Answer 4

Keep in mind that content-types and encodings are two different things. text/html is a content-type; ISO-8859-1 and UTF-8 are encodings.

The HTTP response header that the server sends typically looks like this:

Content-Type: text/html; charset=utf-8

"charset" is actually the character encoding. It's not in a separate header; however there is a header called "Content-Encoding" which actually specifies what kind of compression the response uses (e.g. gzip).

If you want to change the character encoding to UTF-8, in a file that contains HTML:

<?
header("Content-Type: text/html; charset=utf-8");

Answer 5

If your server is not configured to have a default content or charset, and neither is PHP, PHP will send only Content-Type: text/html - it won't specify a charset at all, and will send the bytes as it sees them in the script.

If a browser receives a page without charset specified, various things can happen:

• most browsers have an "Encoding/Charset" menu; if the user explicitly selects one, the browser will try to apply it. Doesn't happen too often, so:
• some browsers try to render it with a default charset (which is locale-dependent, e.g. for FF and cs_CZ it used to be iso-8859-2; YMMV)
• IE will try to determine the charset heuristically (it will take a guess, based on character distribution - and many times it gets it right; sometimes it gets it wrong and you get a page in Romanian interpreted as Chinese text, which usually means "unreadable")
• some old browsers will fall back on us-ascii

If with this procedure, the PHP script's charset and the browser's charset matches, the text will - accidentally - be readable. If not, there will be weird signs and similar phenomena.