Web Specifications Supported in Opera 7

This page applies to the FreeBSD, Linux, Mac, Solaris, Symbian, TRON, and Windows version 7.* of Opera. For Opera version 6, see Specifications for Opera 6.

Opera HTML and XHTML support

Complete table of HTML, XHTML and WML support

HTML 4.01

Opera version 7 supports HTML 4.01 with these exceptions:

The alink property of the body element is not supported
Event attributes are not supported for the option element
The col width attribute does not support multilengths
The table cell attributes char and charoff are not supported.
The lang attribute is not supported.
Support for the table attributes frame and rules were added in version 7.1. The equivalent CSS border properties are supported for all versions.
Support for the bidirectional override element bdo and the dir attribute was added with version 7.2.

XHTML 1.0 and XHTML Modularization

There are two "modes" of XHTML support, one where the document has the text/html content type and the other where it has one of text/xml, application/xml or application/xhtml+xml. In the first case the document is handled as any other HTML document (giving de facto support for XHTML 1.0, XHTML Basic and XHTML 1.1). In the second case XHTML will be treated as XML with predetermined functionality for HTML elements nd attributes. In "XML mode" Opera has the following additional exception:

Support for the script element was added in Opera 7.5.

XHTML 1.1 support

Opera version 7 supports XHTML 1.1 with these exceptions:

Event attributes are not supported for the option element
The table cell attributes char and charoff are not supported.
The lang attribute is not supported.
Ruby annotations are not supported.
The bidirectional override element bdo and the dir attribute were added in Opera 7.2.
Support for the script element was added in Opera 7.5.

XHTML Basic

Opera 7 supports XHTML Basic with no exceptions.

OMA XHTML Mobile Profile

Opera 7 supports the XHTML Mobile Profile 1.0 extensions to XHTML Basic with no exceptions.

WML 1.3 and 2.0 support

Wireless Markup Language versions 1.0 to 1.3, while based on an HTML subset, must be considered a separate markup language for most practical purposes. WML 2.0 can better be considered an extension of XHTML Basic with WML 1.3 features.

Opera 7 supports WML 1.3 and 2.0 with the following exceptions:

The localsrc attribute
The columns attribute
The input formatting code <lang:class>
the wml:getvar element

XML support

Opera 7 can parse and display XML documents. Documents with Content-type "text/xml" or "application/xml" will be treated as an XML document. If a Content-type is not available, the ".xml" file extension will also make the document be treated as XML.

XSL and XSLT

Opera does not support XSL formatting objects, and neither does it natively support XSLT transformations. XML documents transformed server side will be parsed and displayed by Opera just like any other XML document. For an opinion on client side XSL-FO, see Formatting Objects Considered Harmful.

XML namespaces

Opera 7 fully supports XML namespaces. The most common use of namespaces is for XHTML processing. The XHTML namespace (http://www.w3.org/1999/xhtml) triggers XHTML handling in Opera.

CSS support

CSS Level 1

Opera 7 supports all of CSS1.

CSS Level 2

Opera 7 supports all of CSS2 with the exception of:

These properties: font-size-adjust, font-stretch, marker-offset, marks, and text-shadow,
- These properties were added in Opera 7.2: direction and unicode-bidi
The values added to list-style-type in CSS2.
These property/value combinations: "display: marker", "text-align: <string>", "visibility: collapse".
Named pages (as described in section 13.3.2).
The "@font-face" construct.
The :lang() selector

Complete table of CSS level 1 and 2 support

CSS Level 2 Revision 1

CSS 2.1 is currently a W3C Working Draft, compliance is measured against the latest draft, but the final version may differ.

Opera 7.5 supports all of CSS2.1. Earlier versions of Opera had these exceptions:

The direction and unicode-bidi properties before Opera 7.2
The :lang() selector before Opera 7.5

CSS Mobile profile

Opera 7 fully supports CSS Mobile profile.

WAP CSS

WAP CSS is an extension of CSS Mobile Profile. The following WCSS properties are not supported:

-wap-accesskey
-wap-input-format
-wap-input-required
-wap-marquee
-wap-marquee-style
-wap-marquee-loop
-wap-marquee-dir
-wap-marquee-speed

Proposed CSS 3 properties supported by Opera

Note that these properties are at an early stage of development, they may be changed or removed from the specifications at any time. Use them as experimental.

Experimental support for Media Queries
content is applicable on all elements, not just on the :before and :after pseudo-elements
box-sizing

Opera CSS linking extensions

Opera 7 uses CSS-like properties to attach information to XML elements that cannot otherwise be represented. Three extension properties have been implemented to allow hyperlinks and images to be included in XML documents. Most often it's better for authors to use XHTML - rather than the properties described below - to represent document semantics, but they are described here for reference.

CSS Extensions for XML
Property:	-o-link
Values:	none \| attr(<attribute-name>)
Initial:	none
Inherited:	no
Description:	This property sets the value of the "link" variable which can later be used to generate a link through the "-o-link-source" property.
Property:	-o-link-source
Values:	none \| current \| next
Initial:	none
Inherited:	no
Description:	This property sets the element to be a source anchor and, if so, declares which value of the '-o-link' variable that should be used: the current or the next.
Property:	-o-replace
Values:	none \| attr(x)
Initial:	none
Inherited:	no
Description:	This property declares the element to be replaced or not. If replaced, the attr() function is used to point to the attribute where the URI to the content can be found.

In addition Opera accepts a non-standard value for the CSS2 white-space property, namely white-space: -o-pre-wrap. This value is exactly like white-space: pre with the exception that lines will wrap if wider than the containing box. This is particularily handy for plain-text formats with unpredictable position of line break characters, like e-mail messages. Unlike the other white-space settings however, -o-pre-wrap will display tab characters like small boxes.

Some differences from Internet Explorer and Netscape

When using the Opera browser, you may notice that some pages are displayed differently than in other browsers. In most cases, the differences are caused by errors in the pages that are being displayed. Few Web pages are authored according to W3C's specifications which Opera supports. Opera 7 has two rendering modes, Standards Mode and Quirks Mode. For a full documentation on this, see separate document.

The displayed color of an hr is set with the background-color CSS property in Opera and Netscape 6+. In Netscape 4 and IE it is set with the color property. Setting both properties to the desired color will give the same result in all browsers. This will not give the intended effect if content is added to hr with the content property, but Netscape 4 and IE don't support this anyway.
The default style sheet in IE and Netscape gives the body element margin: 8px, Opera uses padding: 8px. Padding is the margin between the body element and the content, while margin is the margin between the body and the html element (or the head element if visible). If either margin or padding is explicitly set on body, the other property should be set too.
The CSS improvements in IE6 are already implemented in Opera. This means that IE6's display of web pages in standards-compliant mode is much closer to Opera's web page display. For further information, see the Microsoft documentation on IE6.

XML and CSS

In order to display an XML document, a CSS style sheet should be present. Authors can attach style sheets to their XML documents through a processing instruction. Here is a simple example:

<?XML version="1.0"?>
<?xml-stylesheet href="shakespeare.css" type="text/css"?>

If no style sheet is present and the page is not namespaced to HTML, Opera 7 will use the initial values on all CSS properties to display the document. All elements will be inline, and all text will be rendered in the same font.

ECMAScript support

Complete table of ECMAScript support

ECMAScript is the standardized version of JavaScript Core. It is being standardized through the ECMA standards body. ECMAScript does not include browser and document related objects.

Opera 7 supports the entire ECMA-262 2ed and 3ed standard, with no exceptions. They are more or less aligned with JavaScript 1.3/1.5 Core.

DOM support

DOM 2 Core

Opera 7 has full support for the Fundamental interfaces, apart from these exceptions:

DOM implementation

createDocumentType()
createDocument()

Document

createCDATASection()
createProcessingInstruction()
createEntityReference()
createElementNS()
createAttributeNS()
getElementsByTagNameNS()

Element

getAttributeNS()
setAttributeNS()
removeAttributeNS()
getAttributeNodeNS()
setAttributeNodeNS()
getElementsByTagNameNS()
hasAttributeNS()

Opera 7 does not support these Extended interfaces:

CDATA
Notation
Entity
EntityReference
ProcessingInstruction

DOM 1 HTML

Opera 7 has full support for this module, apart from these objects:

HTMLHtmlElement

HTMLHeadElement

HTMLIsIndexElement

HTMLOptGroupElement

HTMLDirectoryElement

HTMLBaseFontElement

HTMLMenuElement

and these properties and methods:

HTMLDOMImplementation

createHTMLDocument()

HTMLMetaElement

scheme

HTMLOptionElement

label

HTMLInputElement

maxLength

HTMLImageElement

lowSrc
longDesc

HTMLObjectElement

declare

HTMLScriptElement (partial support)

text
HTMLFor
event

HTMLTableColElement, HTMLTableSectionElement, HTMLTableRowElement, HTMLTableCellElement

ch
chOff

HTMLTableCellElement

abbr

DOM 2 Events

Opera 7 has full support of DOM 2 Events and UI Events interfaces, with no exceptions.

DOM 2 Style

Opera 7 has partial support of DOM 2 Style, consisting of support for these objects:

ElementCSSInlineStyle

CSSStyleDeclaration

Except for these properties and methods:

CSSText
parentRule
getPropertyCSSValue()
getPropertyPriority()

CSS2Properties

Except for these properties:

captionSide
counterIncrement
direction
fontSizeAdjust
fontStretch
markerOffset
marks
tableLayout
textShadow
unicodeBidi
all Aural CSS properties

Support for non-standard JScript and JavaScript objects

In addition to ECMAScript and the DOM objects, Opera supports a number of non-standardized JavaScript/JScript objects.

Anchor

name
text

Button

blur()
click()
focus()

CSSStyleDeclaration

pixelBottom
pixelHeight
pixelLeft
pixelRight
pixelTop
pixelWidth
posBottom
posHeight
posLeft
posRight
posTop
posWidth

document

onClick
onDblClick
onKeyDown
onKeyPress
onKeyUp
onMouseDown
onMouseUp

alinkColor
all
all()
all.tags()
bgColor
embeds
fgColor
formName
height
ids
lastModified
plugins
readyState

event

cancelBubble
data
fromElement
keyCode
offsetX
offsetY
returnValue
srcElement
which
x
y

Form

encoding

History

back()
current
forward()
go()
length
next
previous

HTMLElement

all
clientHeight
clientWidth
innerHTML
innerText
insertAdjacentElement()
insertAdjacentHTML()
insertAdjacentText()
offsetHeight
offsetLeft
offsetParent
offsetTop
offsetWidth
outerHTML
outerText

Image

complete

java

JavaArray

length
toString()

JavaClass

JavaObject

JavaPackage

Location

hash
host
hostname
href
pathname
port
protocol
reload()
replace()
search
toString()
valueOf()

MimeType

description
enabledPlugin
suffixes
type

Navigator

appCodeName
appMinorVersion
appName
appVersion
browserLanguage
cookieEnabled
javaEnabled()
language
mimeTypes
platform
plugins
taintEnabled()
userAgent

Netscape

Option

length

Packages

className
java
netscape
sun

Plugin

description
filename
length
name

screen

availHeight
availWidth
colorDepth
height
pixelDepth
width

Style

align
borderWidths
margins
paddings

Sun

Window

onBlur
onLoad
onUnload

alert()
back()
blur()
clearInterval()
clearTimeout()
close()
closed
confirm()
defaultStatus
disableExternalCapture()
document
enableExternalCapture()
event
focus()
forward()
frames
history
home()
innerHeight
innerWidth
java
length
location
moveBy()
moveTo()
name
open()
opener
outerHeight
outerWidth
Packages
pageXOffset
pageYOffset
parent
print()
prompt()
releaseEvents()
resizeBy()
resizeTo()
screenLeft
screenTop
screenX
screenY
scrollBy()
scrollTo()
self
setInterval() (partial support)
setTimeout() (partial support)
status
stop()
top
window

window.<frame-name>
window.<element-name>
window.<element-id>

Networking protocols support

Opera 7 has full support for HTTP 1.0 and HTTP 1.1. Here are some highlights:

Persistent connections (multiple request/response through one connection)
Cachecontrol for no-cache (always check for fresh document) and no-store (don't save to disk)
Basic Authentication (passwords). Supports Digest Authentication, excepting integrity check on body. No current plans to support NTLM
Resume download, provided the server supports it
SSL/TLS support (also through proxy/firewall)
Proxy for HTTP, FTP, Gopher and WAIS

Encryption: 128 bit encryption (RSA key exchange only) for the Secure Sockets Layer (SSL) versions 2 and 3, and the successor Transport Layer Security (TLS) v1.0. This is supported for HTTP (web), NNTP (news), POP and SMTP e-mail). Support for generating private keys and submitting certificate requests.

News: simple online newsreader with support for encrypted newsservers and newsserver with passwords. Can decode single article attachments, MIME or uuencoded.

FTP including resume download is supported.

It is possible to download to file for both FTP and HTTP.

Text and internationalization

Unicode support in Opera

Opera can work with all the characters in the Unicode specification. All text communicated to Opera from the network is converted into Unicode.

In order for Opera to render Unicode characters, the needed glyphs have to be available in the fonts on your system. This might be a problem for older Windows systems. For information on available fonts, see Unicode fonts for Windows computers.

Opera 7 implements the following writing system related functionality:

font-switching: Needed in order to display characters that the current font does not include.
line-breaking: Needed in order to break scripts written without spaces, such as Chinese, Korean, and Japanese.

Opera relies on the operating system to perform:

character shaping: Contextual glyph selection, ligature forming, character stacking, combining character support etc.

Legacy encoding support

Although Opera works with Unicode encodings (UTF-16 and UTF-8), most text on the Internet is encoded in legacy encodings, for instance ISO 8859-1, Windows-1251, Shift-JIS, EUC-KR. Opera handles this by detecting the character encoding used, and converting it to UTF-16. The user has three options for how to handle these pages.

Auto-detect: In this mode Opera will attempt to detect the encoding used by the page. If the transport protocol provides an encoding name, that is used. If not, Opera will look at the page for a charset declaration. If this is missing, Opera will attempt to auto-detect the encoding, using the domain name to see if the script is a CJK script, and if so which one. Opera can also auto-detect UTF-8.
Writing script auto-detect: In this mode the user can tell that this is a Japanese or Chinese page, but that the encoding is unknown. Opera will then analyze the text in the page to determine which encoding is used.
Encoding override: In this mode the user selects an encoding. This encoding will be used by Opera, regardless of what the page and transport protocol claims is the encoding for the page.

This table shows all the legacy encodings Opera supports in addition to Unicode:

Legacy Encodings
Encoding	Category	Comments
ISO 8859-1	Latin
ISO 8859-2	Latin	Used in Eastern Europe
ISO 8859-3	Latin	Rare
ISO 8859-4	Latin	Sami and Baltic country
ISO 8859-9	Latin	Turkish
ISO 8859-10	Latin	Inuit, Sami, and Icelandic
ISO 8859-13	Latin	Rare
ISO 8859-14	Latin	Celtic
ISO 8859-15	Latin	Intended to supersede 8859-1
Windows-1250	Latin	Used in Eastern Europe
Windows-1252	Latin
Windows-1254	Latin	Turkish
Windows-1257	Latin	Baltic
Windows-1258	Latin	Vietnamese
VISCII	Latin	Vietnamese
IBM 866	Cyrillic
ISO 8859-5	Cyrillic
koi8-r	Cyrillic
koi8-u	Cyrillic	Ukrainian version of koi8-r
Windows-1251	Cyrillic
ISO 8859-6	Arabic
Windows-1256	Arabic
ISO 8859-7	Greek
Windows-1253	Greek
ISO 8859-8	Hebrew
Windows-1255	Hebrew
ISO 8859-11	Thai	Also known as TIS-620
Windows-874	Thai	Extension of ISO 8859-11
utf-8	Unicode
utf-16	Unicode
Shift-JIS	Japanese
ISO-2022-JP	Japanese
EUC-JP	Japanese
Big 5	Chinese
EUC-CN	Chinese	Also erroneously known as GB 2312
HZ-GB-2312	Chinese	Primarily used in e-mail
EUC-TW	Chinese
GBK	Chinese	EUC-CN extension
EUC-KR	Korean

Support for bidirectional text

With version 7.2 Opera supports bidirectional text as described in Unicode, HTML, and CSS.

Graphics support

Opera fully supports GIF89a, JPEG, BMP, ICO, WBMP and has full support for PNG including alpha channel (degrees of transparency) and gamma support (device independent colors).