Test results: CSS encoding

Summary & conclusions

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 or XHTML 1.1 served as application/xhtml+xml.

All user agents but IE7 supported encoding declarations using HTTP and all supported @charset. Only IE8, Firefox, Opera support encoding declarations using the charset attribute.

Only IE and Firefox appear to respect the rule that a CSS file with no encoding declaration assumes the encoding of the HTML file that called it. In this situation Opera seems to default to UTF-8, while Safari and Chrome default to ISO Latin 1.

Other conclusions are TBD for now.

Latest results

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. To view the assertion, mouse over the text in the left column.

Results are given for five 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), X11 (XHTML 1.1, served as XML). Results across all formats were the same for all tests, so only one cell per test per browser is included in the table.

The basic declarations tests come in sets of three; a feature is only supported if the result is positive for all three tests in a group (this is to account for different default encodings).

Basic declarations

	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	20100412	20100412	20100412	20100412	20100412	20100412
HTTP declarations	html utf8, css http iso1 The user agent respects the encoding of a css stylesheet declared in HTTP.	yes	no	yes	yes	yes	yes
	html utf8, css http iso15 The user agent respects the encoding of a css stylesheet declared in HTTP.	yes	no	yes	yes	yes	yes
	html iso1, css http utf8 The user agent respects the encoding of a css stylesheet declared in HTTP.	yes	no	yes	yes	yes	yes
@charset declarations	html utf8, css @charset iso1 The user agent respects the encoding of a css stylesheet declared in an @charset rule.	yes	yes	yes	yes	yes	yes
	html utf8, css @charset iso15 The user agent respects the encoding of a css stylesheet declared in an @charset rule.	yes	yes	yes	yes	yes	yes
	html iso1, css @charset utf8 The user agent respects the encoding of a css stylesheet declared in an @charset rule.	yes	yes	yes	yes	yes	yes
link charset	html utf8, link charset iso1 The user agent respects the encoding of a css stylesheet declared in a charset attribute on the HTML link.	yes	no	yes	yes	yes	yes
	html utf8, link charset iso15 The user agent respects the encoding of a css stylesheet declared in a charset attribute on the HTML link.	yes	no	yes	yes	no	no
	html iso-8859-1, link charset utf8 The user agent respects the encoding of a css stylesheet declared in a charset attribute on the HTML link.	yes	no	yes	yes	no	no
Inheritance from HTML encoding	html iso1 The user agent applies the encoding of the HTML file to a css stylesheet whose encoding is not otherwise declared.	yes	yes	yes	no	yes	yes
	html iso15 The user agent applies the encoding of the HTML file to a css stylesheet whose encoding is not otherwise declared.	yes	yes	yes	no	no	no
	html utf8 The user agent applies the encoding of the HTML file to a css stylesheet whose encoding is not otherwise declared.	yes	yes	yes	yes	no	no

Assertion:  

Link to tests: HTTP declarations - @charset declarations - link charset - Inheritance from HTML encoding

UTF-8 signature

	UA	IE	IE	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	20100412	20100412	20100412	20100412	20100412	20100412
UTF-8 signature	html iso-8859-1, css bom The user agent uses a UTF-8 signature without an @charset at the beginning of a css stylesheet to indicate that the encoding is UTF-8.	yes	yes	yes	yes	yes	yes
	html iso-8859-15, css bom The user agent uses a UTF-8 signature without an @charset at the beginning of a css stylesheet to indicate that the encoding is UTF-8.	yes	yes	yes	yes	yes	yes
@charset and BOM	html iso-8859-1, css bom and @charset utf8 (in lowercase) When a stylesheet has a BOM and an @charset declaration that is for the right Unicode encoding, the stylesheet works.	yes	yes	yes	yes	yes	yes
	html iso-8859-1, css bom and @charset utf8 (in uppercase) When a stylesheet has a BOM and an @charset declaration that is for the right Unicode encoding, the stylesheet works.	yes	yes	yes	yes	yes	yes
	html iso-8859-15, css bom and @charset iso15 When a stylesheet has a BOM and a @charset declaration that is not for a Unicode encoding, the stylesheet fails.	no	yes	yes	no	no	no

Assertion:  

Link to tests: UTF-8 signature - @charset and BOM

Unknown encoding

UA	IE	IE	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	20100412	20100412	20100412	20100412	20100412	20100412
html utf-8, css @charset unknown When a stylesheet has a @charset declaration with an unknown value, the stylesheet should be ignored.	yes	no	yes	no	no	no

Assertion:  

Link to tests: Unknown encoding

Typos

These tests are only valid if the @charset rule is recognized by the user agent. The result of that test is shown on the first data row.

UA	IE	IE	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	20100412	20100412	20100412	20100412	20100412	20100412
html utf8, css @charset iso15 The user agent respects the encoding of a css stylesheet declared in an @charset rule.	yes	yes	yes	yes	yes	yes
no semicolon at end of charset rule If a @charset declaration is missing a final semicolon, the encoding declaration will not be recognised.	yes	no	yes	no	yes	yes
extra spaces after @charset If a @charset declaration has more than one space after 'charset', the encoding declaration will not be recognised.	yes	no	yes	no	no	no
extra spaces before colon in charset rule If a @charset declaration has spaces just before the colon, the encoding declaration will not be recognised.	yes	no	yes	no	no	no
linebreak in middle of charset rule If a @charset declaration has a line break in the middle, the encoding declaration will not be recognised.	yes	no	yes	no	yes	yes
single quotes around charset name If a @charset declaration value has single, rather than double, quotes around it, the encoding declaration will not be recognised.	yes	no	yes	no	no	no
blank line before @charset If a @charset declaration is not on the first line of the file, the encoding declaration will not be recognised.	yes	yes	yes	yes	1	yes
spaces before @charset If a @charset declaration does not start at the beginning of the first line of the file (when there is no BOM), the encoding declaration will not be recognised.	yes	yes	yes	yes	1	yes

Assertion:  

Link to tests: typos

Notes:

1. Style sheet wasn't loaded at all.

Precedence

These tests are only valid if the relevant HTTP declarations, @charset rules and charset links have an effect. The results for those tests are shown on the first two data rows.

UA	IE	IE	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	20090417	20090417	20090417	20090417	20090417	20090417
html utf8, css @charset iso15 The user agent respects the encoding of a css stylesheet declared in an @charset rule.	yes	yes	yes	yes	yes	yes
html utf8, link charset iso15 The user agent respects the encoding of a css stylesheet declared in a charset attribute on the HTML link.	yes	no	yes	yes	no	no
http vs. @charset An HTTP encoding declaration for a stylesheet takes precedence over an @charset declaration.	yes	no	yes	yes	yes	yes
http vs. charset link An HTTP encoding declaration for a stylesheet takes precedence over a charset attribute link declaration.	yes	n/a	yes	yes	n/a	n/a
http vs. bom An HTTP encoding declaration for a stylesheet takes precedence over a UTF-8 signature.	yes	no	yes	yes	no	no
@charset vs. charset link An HTTP encoding declaration for a stylesheet takes precedence over a UTF-8 signature.	yes	n/a	yes	yes	n/a	n/a

Assertion:  

Link to tests: Precedence