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How can I check the character encoding information sent in the HTTP header of a web document?
It is important to clearly indicate the character encoding (charset) of a
document served on the Web. Otherwise,a receiver may not correctly interpret the document. A Web browser, for example, may show random characters
instead of readable text. One way of indicating the character encoding of a Web document is to put this information into the charset
parameter of the Content-Type header.
There are several ways to check the actual Web document served, including the headers:
There are several services that show you all the HTTP headers and the (HTML/XHTML) source of the document returned from the server after you enter the address of the document you are interested in:
Note: W3C has no relationship to any of these services.
In the HTTP headers, look for the Content-Type header, and in particular for the charset parameter, e.g.
Content-Type: text/html; charset=utf-8
Note: The charset parameter may not be present. This is okay if your document itself indicates its character
encoding.
To check the markup, the Markup Validation Service has to make sure it correctly decodes the document it checks. It will show an error message if it cannot find information about the encoding, or if it finds conflicting information, or if it cannot decode the document according to the information it found.
To know the encoding that the validator found, you can use the extended interface.
In this interface, you can also select the show source option, and then visually check that the source is
correctly interpreted. This is useful to check that you actually use the right encoding. It is not always possible to mechanically check
whether for example, a document claiming to be iso-8859-1 is actually encoded using iso-8859-2 or some other encoding.
telnet or another command-line toolThis requires a bit more expertise, but may be easier to automate. Another command line tool may be wget (with a
-S or -s option).
Some servers transcode the Web documents they serve to different character encodings for different clients. This happens for example with some servers in Russia. This requires special care, because your browser, running e.g. on a Mac or on a Windows system, may indicate using a different character encoding than the encoding given to you by a Web-based service or the W3C Markup Validation Service (which are mostly based on UNIX systems).
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Content first published 2003-06-16. Last substantive update 2004-11-25 12:13 GMT. This version 2006-11-25 19:21 GMT
Page location: http://www.w3.org/International/questions/qa-headers-charset.en.php
For the history of document changes, search for qa-headers-charset in the i18n blog.
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