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These tests check whether user agents recognise character encoding declarations for HTML and XHTML documents, and apply the expected prioritisation in case of mismatches between multiple declarations.
See the results below for user agents tested. This section summarizes the results of those tests. In what follows, 'HTML' means HTML4.01, HTML5, or XHTML 1.0 served as text/html. XML means XHTML 1.0, XHTML5, or XHTML 1.1 served as application/xhtml+xml.
All user agents detected character encodings declared in the HTTP header for HTML and XML.
All user agents use a UTF-8 BOM to set the page encoding in the absence of any other encoding information. Likewise for little- and big-endian UTF-16 BOMs (though only the HTML5 format was tested.)
The XML declaration was used by all XML pages, but was also used by HTML documents for all browsers tested apart from IE. This use for HTML is not specified. (Note that this test, like the others in this section, uses the XML declaration as the only source of information about encoding.)
The meta Content-Type element was used to set the encoding for HTML but not XML.
The HTML5 charset meta element was recognized for HTML, but not for XML by all browsers. (Note that this syntax is not described in the HTML 4.01 specification, but is in HTML5, so documents containing this declaration do not validate.)
If a charset attribute was added to an a element that pointed to an HTML file with no other encoding information, only Opera rendered the target page with the specified encoding.
On the whole, the precedence rules described in the HTML5 specification are all followed by all browsers tested, ie. HTTP header trumps all; BOM overrides all in-document declarations; XML declaration wins over meta declarations for XML, and vice versa for HTML.
There are the following differences:
When both a meta Content-Type and HTML5 meta charset declaration appear in an HTML page, the first always trumps the second.
These are results for the latest versions of each user agent tested. A green background (yes) means that the assertion associated with the test held true; red (no) means that it did not; orange (partially) means that it was only partially true. Mouse over the left column to view the assertion.
Results are given for four types of document format: H4 (HTML 4.01), H5 (HTML5), XH (XHTML 1.0 served as text/html), X (XHTML 1.0 served as XML), X5 (XHTML5), X11 (XHTML 1.1, served as XML). The UTF-16 tests are run only in the HTML5 format. Internet Explorer doesn't handle pages served as XML, so those tests are ignored in these results.
| UA | IE | Firefox | Opera | Safari | Chrome | ||||
|---|---|---|---|---|---|---|---|---|---|
| version | 8 | 3.6.3 | 10.51 | 4.05 | 4.1.249.1045 | ||||
| OS | XP | XP | XP | XP | XP | ||||
| date | 20100414 | 20100414 | 20100414 | 20100414 | 20100414 | ||||
| format | H4,H5,XH | H4,H5,XH | X,X5,X11 | H4,H5,XH | X,X5,X11 | H4,H5,XH | X,X5,X11 | H4,H5,XH | X,X5,X11 |
| HTTP charset declaration: Setting the HTTP header charset declaration will will affect the encoding of a page. | yes |
yes |
yes | yes |
yes | yes | yes | yes | yes |
| UTF-8 BOM: A page with no encoding declarations, but with a UTF-8 signature will be recognized as UTF-8. | no | no | yes | no | yes | no | yes | no | yes |
| UTF-16LE BOM: A page with no encoding declarations, but with a UTF-16 little-endian BOM will be recognized as UTF-16. | yes1 | yes1 | yes1 | yes1 | yes1 | yes1 | yes1 | yes1 | yes1 |
| UTF-16BE BOM: A page with no encoding declarations, but with a UTF-16 big-endian BOM will be recognized as UTF-16. | yes1 | yes1 | yes1 | yes1 | yes1 | yes1 | yes1 | yes1 | yes1 |
| XML declaration: Setting the encoding in the XML declaration will affect the encoding of a page served as XML, but will not affect pages served as text/html. | yes | no2 | yes | no2 | yes | no2 | yes | no2 | yes |
| meta Content-Type charset declaration: Setting the encoding in the meta Content-Type element will affect the encoding of a page served as text/html, but will not affect pages served as XML. | yes | yes | yes | yes | yes | yes | yes | yes | yes |
| HTML5 meta charset declaration: Setting the encoding in the HTML5 meta charset element will affect the encoding of a page served as text/html, but will not affect pages served as XML. | yes | yes | yes | yes | yes | yes | yes | yes | yes |
| charset on an a element A link to a page using the a element with a charset attribute will cause a page with no other encoding information to be rendered using the encoding in the charset attribute. | no | no | no | yes | yes | no | no | no | no |
Assertion:
Link to tests: Basic tests
Notes:
| UA | IE | IE | Firefox | Opera | Safari | Chrome | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| version | 8 | 7 | 3.6.3 | 10.51 | 4.05 | 4.1.249.1045 | ||||
| OS | XP | XP | XP | XP | XP | XP | ||||
| date | 20100414 | 20100414 | 20100414 | 20100414 | 20100414 | 20100414 | ||||
| format | H4,H5,XH | H4,H5,XH | H4,H5,XH | X,X5,X11 | H4,H5,XH | X,X5,X11 | H4,H5,XH | X,X5,X11 | H4,H5,XH | X,X5,X11 |
| HTTP vs UTF-8 BOM: If the HTTP header of a page is not set to UTF-8, a UTF-8 BOM will not cause a file to be treated as UTF-8. | no |
no |
yes |
yes | yes |
yes | no | no | no | no |
| HTTP vs UTF-16LE BOMIf the HTTP header of a page is not set to UTF-16, a UTF-16 little-endian BOM will not cause a file to be recognized as UTF-16. | no1 | no1 | yes1 | yes1 | yes1 | yes1 | no1 | no1 | no1 | no1 |
| HTTP vs UTF-16BE BOMIf the HTTP header of a page is not set to UTF-16, a UTF-16 big-endian BOM will not cause a file to be recognized as UTF-16. | no1 | no1 | yes1 | yes1 | yes1 | yes1 | no1 | no1 | no1 | no1 |
| HTTP vs XML declarationThe HTTP header has a higher precedence than an XML declaration. | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes |
| HTTP vs meta Content-TypeThe HTTP header has a higher precedence than a meta Content-Type encoding declaration. | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes |
| HTTP vs HTML5 metaThe HTTP header has a higher precedence than an HTML5 meta encoding declaration. | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes |
| UTF-8 BOM vs XML declarationA page with a UTF-8 BOM will be recognized as UTF-8 even if the XML declaration declares a different encoding. | yes |
yes |
yes |
yes | yes |
yes | yes | yes | yes | yes |
| UTF-8 BOM vs meta Content-Type A page with a UTF-8 BOM will be recognized as UTF-8 even if the meta Content-Type declares a different encoding. | no | no | no2 | yes | yes | yes | yes | yes | yes | yes |
| UTF-8 BOM vs HTML5 meta charset A page with a UTF-8 BOM will be recognized as UTF-8 even if the HTML5 meta charset declares a different encoding. | yes | yes | no2 | yes | yes | yes | yes | yes | yes | yes |
| UTF-16LE BOM vs XML declaration A page with a UTF-16 little-endian BOM will be recognized as UTF-16 even if the XML declaration declares a different encoding. | yes1 | yes1 | yes1 | yes1 | yes1 | yes1 | yes1 | yes1 | yes1 | yes1 |
| UTF-16LE BOM vs meta Content-Type A page with a UTF-16 little-endian BOM will be recognized as UTF-16 even if the meta Content-Type element declares a different encoding. | yes1 | yes1 | yes1 | yes1 | yes1 | yes1 | yes1 | yes1 | yes1 | yes1 |
| UTF-16LE BOM vs HTML5 meta charset A page with a UTF-16 little-endian BOM will be recognized as UTF-16 even if the meta charset element declares a different encoding. | yes1 | yes1 | yes1 | yes1 | yes1 | yes1 | yes1 | yes1 | yes1 | yes1 |
| XML declaration vs meta Content-Type The XML declaration has a higher precedence than a meta Content-Type encoding declaration for pages served as XML, but not for pages served as text/html. | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes |
| XML declaration vs HTML5 meta The XML declaration has a higher precedence than an HTML5 meta encoding declaration for pages served as XML, but not for pages served as text/html. | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes |
| meta Content-Type, then HTML5 meta A meta Content-Type encoding declaration has a higher precedence than a following HTML5 meta encoding declaration. | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes |
| HTML5 meta, then meta Content-Type An HTML5 meta encoding declaration has a higher precedence than a following meta Content-Type encoding declaration. | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes |
Assertion:
Link to tests: Precedence
Notes:
This section provides additional information about older UA versions, where that information exists. It does not provide enough information to trace the history of feature support in a given UA. The conventions used are as described in the previous section.
| UA | IE1 | IE1 | Firefox | Opera | Safari | Chrome | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| version | 8 | 7 | 3.5.1 | 9.64 | 4.0.2 | 2.0.172.37 | ||||||||||||||||||
| OS | XP | XP | XP | XP | XP | XP | ||||||||||||||||||
| date | 20090717 | 20090717 | 20090717 | 20090717 | 20090717 | 20090717 | ||||||||||||||||||
| format | H4 | XH | X | X11 | H4 | XH | X | X11 | H4 | XH | X | X11 | H4 | XH | X | X11 | H4 | XH | X | X11 | H4 | XH | X | X11 |
| HTTP charset declaration | yes | yes | n/a | n/a | yes | yes | n/a | n/a | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes |
| XML declaration | yes | yes | n/a | n/a | yes | yes | n/a | n/a | no1 | no1 | yes | yes | no1 | no1 | yes | yes | no1 | no1 | yes | yes | no1 | no1 | yes | yes |
| meta Content-Type charset declaration | yes | yes | n/a | n/a | yes | yes | n/a | n/a | yes | yes | yes | yes | yes | yes | no3 | no3 | yes | yes | yes | yes | yes | yes | yes | yes |
| HTML5 meta charset declaration | yes | yes | n/a | n/a | yes | yes | n/a | n/a | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes |
Notes:
| UA | IE1 | IE1 | Firefox | Opera | Safari | Chrome | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| version | 8 | 7 | 3.5.1 | 9.6.4 | 4.0.2 | 2.0.172.37 | ||||||||||||||||||
| OS | XP | XP | XP | XP | XP | XP | ||||||||||||||||||
| date | 20090717 | 20090717 | 20090717 | 20090717 | 20090717 | 20090717 | ||||||||||||||||||
| format | H4 | XH | X | X11 | H4 | XH | X | X11 | H4 | XH | X | X11 | H4 | XH | X | X11 | H4 | XH | X | X11 | H4 | XH | X | X11 |
| HTTP vs meta Content-Type | yes | yes | n/a | n/a | yes | yes | n/a | n/a | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes |
| HTTP vs HTML5 meta | yes | yes | n/a | n/a | yes | yes | n/a | n/a | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes |
| HTTP vs XML declaration | yes | yes | n/a | n/a | yes | yes | n/a | n/a | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes |
| XML declaration vs meta Content-Type | yes | yes | n/a | n/a | yes | yes | n/a | n/a | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes |
| XML declaration vs HTML5 meta | yes | yes | n/a | n/a | yes | yes | n/a | n/a | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes |
| meta Content-Type, then HTML5 meta | yes | yes | n/a | n/a | yes | yes | n/a | n/a | yes | yes | yes | yes | yes | yes | no | yes | yes | yes | yes | yes | yes | yes | yes | yes |
| HTML5 meta, then meta Content-Type | yes | yes | n/a | n/a | yes | yes | n/a | n/a | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes |
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Content first published 2009-04-16. Last substantive update 2009-07-18 7:00 GMT. This version 2010-04-12 12:02 GMT
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