HTTP for HTML Authors, Part II
|
| ||||
| ||||
|
|
Specifying the content language
Content-Type is the most important header describing the content transferred through HTTP. In fact, every HTTP request or response that involves any kind of content other than headers and response codes must include a Content-Type header so that the receiving end can figure out what to do with what it's receiving.
However, there are a couple of other headers that might also be of interest to HTML authors. The most important one is called Content-Language and is used to specify the language of the document being transferred.
Note that the language is something related, but different, to the encoding. The language of the document is simply the human-spoken language the the document is written in. The document you are reading right now is written in Engish, so an appropriate Content-Language header for it would be something like the following:
Content-Language: en
If you're being particular about things, you might even what to specify that this document is written in American English and add a little local color (as opposed to local colour) with something like this:
Content-Language: en-US
As you may have gathered by now, languages are specified using a two-letter language code as defined by ISO, followed by an optional dash and a modifier indicating a variant of the language.
The way to pick the language you send with the Content-Language header is to think about what language your audience must be fluent in in order to understand the document. So a document written in English with a couple of phrases in French put in to express abstract ideas or to impress members of the opposite sex would still only have the en language specified. On the other hand, a document which contains, for instance, a international treaty written in both English and French would have to specify that the reader can enjoy (or not, as the case may be) the document whether he speaks English or French. In this case, you can specify multiple languages separated by commas, like so:
Content-Language: en, fr
Specifying the content language can have many uses. One of them is content negotiation, which we'll discuss next. Another, very important use is for non-browser user agents. An example would be a search engine robot that could know that your document was written in a specific language and will return it as a result for searches of documents in the specific language; most search engine support this feature, so setting up your Web server to send the right language as part of the HTTP request will help your search engine rankings.
