W3C

网站内容无障碍指南2.0 / Web Content Accessibility Guidelines (WCAG) 2.0 中文版

2008年12月11日 W3C 推荐标准

当前版本:
http://www.w3.org/TR/2008/REC-WCAG20-20081211/
最新版本:
http://www.w3.org/TR/WCAG20/
上一版本
http://www.w3.org/TR/2008/PR-WCAG20-20081103/
编辑:
Ben Caldwell, Trace R&D Center, University of Wisconsin-Madison
Michael Cooper, W3C
Loretta Guarino Reid, Google, Inc.
Gregg Vanderheiden, Trace R&D Center, University of Wisconsin-Madison
前任编辑:
Wendy Chisholm (until July 2006 while at W3C)
John Slatin (until June 2006 while at Accessibility Institute, University of Texas at Austin)
Jason White (until June 2005 while at University of Melbourne)
翻译:
Rocky Wen, Tencent
校验:
Claire Wu, Tencent
Curls Li, Tencent
Dream Wan, Tencent
Vinci Cao, Tencent
Wenju Li, Tencent

网站内容无障碍指南2.0勘误表。(可能包含对规范的修正)

网站内容无障碍指南2.0其他语言译本

WCAG2.0也提供非规范格式,参见网站内容无障碍指南2.0替代版本/Alternate Versions of Web Content Accessibility Guidelines 2.0


摘要

网站内容无障碍指南2.0包含一个广泛的、使网站内容更易于访问的建议。遵循这些指南可以让网站内容对于广泛的残障人士同样拥有可访问性,包括全盲和低视力、失聪和听力衰退、学习障碍、精神局限、行动受限、语言障碍、光敏性以及多重残障。遵循这些指南也会让你的网站内容对正常用户更加容易使用。

WCAG2.0成功标准是不做技术限定的可测试说明。指南提供了单独的文档来说明满足成功标准的特定技术以及对成功标准解释的信息。访问网站无障碍指南概况 / Web Content Accessibility Guidelines (WCAG) Overview查看介绍和WCAG技术以及培训资料的链接。

WCAG2.0继承了W3C在1999年三月发布的推荐标准网站内容无障碍指南1.0 / Web Content Accessibility Guidelines 1.0[WCAG10]。虽然网站内容可能符合WCAG1.0或WCAG2.0,或者两者都符合,但是W3C建议新创建的以及升级的内容要使用WCAG2.0。W3C也建议网站无障碍政策应以WCAG2.0为参考。

文档状态


目录


WCAG2.0指南

本节为规范内容。

Principle 1: Perceivable - Information and user interface components must be presentable to users in ways they can perceive.
原则1:可感知的——信息和用户界面组件必须以用户可感知的方式呈现。

Guideline 1.1 Text Alternatives: Provide text alternatives for any non-text content so that it can be changed into other forms people need, such as large print, braille, speech, symbols or simpler language.
指南1.1 文本替代方案:为所有非文本内容提供文本替代方案,使其可以转化为用户需要的其他格式,比如,大字排版、盲文、语音、符号或者更简单的语言。

1.1.1 Non-text Content: All non-text content that is presented to the user has a text alternative that serves the equivalent purpose, except for the situations listed below. (Level A)
1.1.1非文本内容:所有展示给用户的非文本内容都要有一个提供等价目的的文本替代方案。除了下面列出的情况:(A级)

Guideline 1.2 Time-based Media: Provide alternatives for time-based media.
指南1.2 基于时间的媒体:为基于时间的媒体提供替代方案。

1.2.1 Audio-only and Video-only (Prerecorded): For prerecorded audio-only and prerecorded video-only media, the following are true, except when the audio or video is a media alternative for text and is clearly labeled as such: (Level A)
1.2.1纯视频和纯音频(预先录制的):对于预先录制好的纯音频和纯视频,要遵循下面要求,除非视频或音频是文字的媒体替代方案并且清晰地标明。(A级)
1.2.2 Captions (Prerecorded): Captions are provided for all prerecorded audio content in synchronized media, except when the media is a media alternative for text and is clearly labeled as such. (Level A)
1.2.2字幕(预先录制好的):为同步媒体中所有预先录制好的音频提供字幕,除非媒体是文字的媒体替代方案并且清晰地标明。(A级)
1.2.3 Audio Description or Media Alternative (Prerecorded): An alternative for time-based media or audio description of the prerecorded video content is provided for synchronized media, except when the media is a media alternative for text and is clearly labeled as such. (Level A)
1.2.3音频描述或者媒体代替方案(预先录制好的):为同步媒体提供基于时间的媒体替代方案或者预先录制的视频的音频描述,除非媒体是文字的媒体替代方案并且清晰的表明。(A级)

1.2.4 Captions (Live): Captions are provided for all live audio content in synchronized media. (Level AA)
1.2.4字幕(直播):为同步媒体中的所有直播的音频内容提供字幕。(AA级)
1.2.5 Audio Description (Prerecorded): Audio description is provided for all prerecorded video content in synchronized media. (Level AA)
1.2.5音频描述(预先录制好的):为同步媒体中的左右预先录制的视频提供音频描述。(AA级)

1.2.6 Sign Language (Prerecorded): Sign language interpretation is provided for all prerecorded audio content in synchronized media. (Level AAA)
1.2.6手语(预先录制好的):为同步媒体中的所有预先录制好的音频内容提供手语解释。(AAA级)
1.2.7 Extended Audio Description (Prerecorded): Where pauses in foreground audio are insufficient to allow audio descriptions to convey the sense of the video, extended audio description is provided for all prerecorded video content in synchronized media. (Level AAA)
1.2.7扩展的音频描述(预先录制好的):当前景音暂停,音频描述不足以传达视频的意义时,要为同步媒体中所有预先录制好的音频内容提供扩展的音频描述。(AAA级)
1.2.8 Media Alternative (Prerecorded): An alternative for time-based media is provided for all prerecorded synchronized media and for all prerecorded video-only media. (Level AAA)
1.2.8媒体替代方案(预先录制好的):为所有预先录制好的同步媒体和预先录制好的纯视频媒体提供基于时间的媒体替代方案。(AAA级)
1.2.9 Audio-only (Live): An alternative for time-based media that presents equivalent information for live audio-only content is provided. (Level AAA)
1.2.9纯音频(直播):为直播的纯音频内容提供用于展示等价信息的基于时间的媒体替代方案。(AAA级)

Guideline 1.3 Adaptable: Create content that can be presented in different ways (for example simpler layout) without losing information or structure.
指南1.3 适应性:在不丢失信息和结构的情况下,创建的内容可以在不通的方式中展现。例如:更简单的布局。

1.3.1 Info and Relationships: Information, structure, and relationships conveyed through presentation can be programmatically determined or are available in text. (Level A)
1.3.1信息和关系:表现所传递出的信息、结构、关系可以通过编程方式决定或者以有效的文本形式存在。(A级)
1.3.2 Meaningful Sequence: When the sequence in which content is presented affects its meaning, a correct reading sequence can be programmatically determined. (Level A)
1.3.2 顺序是有意义的:当内容的顺序可以影响它本身的含义,可以利用程序来确定一个正确的阅读顺序(A级)
1.3.3 Sensory Characteristics: Instructions provided for understanding and operating content do not rely solely on sensory characteristics of components such as shape, size, visual location, orientation, or sound. (Level A)
1.3.3 感官特征:为理解和操作内容提供的说明不应该仅仅依赖于组件的感官特征,比如:形状、大小、视觉位置、方向或者声音。(A级)

Note: For requirements related to color, refer to Guideline 1.4.
注:颜色相关的要求,参看:指南1.4

Guideline 1.4 Distinguishable: Make it easier for users to see and hear content including separating foreground from background.
指南1.4 可辨别的:使用户更容易看到和听到内容,包括区分前景色和背景色。

1.4.1 Use of Color: Color is not used as the only visual means of conveying information, indicating an action, prompting a response, or distinguishing a visual element. (Level A)
颜色的使用:颜色不应做为传递信息、指示操作、提示响应或者区别可视元素的唯一方法。(A级)

Note: This success criterion addresses color perception specifically. Other forms of perception are covered in Guideline 1.3 including programmatic access to color and other visual presentation coding.
提示:这个成功标准专门解决颜色的感知。指南1.3涵盖了其他感知形式,包括以编程的方式获取颜色和其他视觉表现的代码。

1.4.2 Audio Control: If any audio on a Web page plays automatically for more than 3 seconds, either a mechanism is available to pause or stop the audio, or a mechanism is available to control audio volume independently from the overall system volume level. (Level A)
1.4.2音频控制:如果一个网页上任何自动播放的音频超过3秒,就需要一个暂停或者停止的有效机制,或者一个独立于所有系统声音级别的控制音频声音有效机制。(A级)

Note: Since any content that does not meet this success criterion can interfere with a user's ability to use the whole page, all content on the Web page (whether or not it is used to meet other success criteria) must meet this success criterion. See Conformance Requirement 5: Non-Interference.
提示:由于任何未能满足此成功标准的内容都会干扰用户使用整个网页,所以网页上的所有内容(无论它是否满足其他的成功标准)都必须实现这个成功标准。参看:一致性要求5:互不干涉。


1.4.3 Contrast (Minimum): The visual presentation of text and images of text has a contrast ratio of at least 4.5:1, except for the following: (Level AA)
1.4.3对比度(最小值):除了下面几点,文本和图片式文本的视觉感知的对比度比至少为4.5:1:(AA级)
1.4.4 Resize text: Except for captions and images of text, text can be resized without assistive technology up to 200 percent without loss of content or functionality. (Level AA)
1.4.4调整文本:除了字幕和图片式文本,在不使用辅助技术的情况下文本可以放大到200%并且没有内容和功能的损失。
1.4.5 Images of Text: If the technologies being used can achieve the visual presentation, text is used to convey information rather than images of text except for the following: (Level AA)
1.4.5图片式文字:如果视觉感知方式能用技术能实现,除了下列情况,使用文本传递信息要比图片式文字好:(AA级)

Note: Logotypes (text that is part of a logo or brand name) are considered essential.
提示:logo类(logo或者品牌名称的一部分)必须要考虑。


1.4.6 Contrast (Enhanced): The visual presentation of text and images of text has a contrast ratio of at least 7:1, except for the following: (Level AAA)
1.4.6对比度(增强的):除了下列情况,文本和图片式文本的视觉感知的对比度比最少为7:1:(AAA级)
1.4.7 Low or No Background Audio: For prerecorded audio-only content that (1) contains primarily speech in the foreground, (2) is not an audio CAPTCHA or audio logo, and (3) is not vocalization intended to be primarily musical expression such as singing or rapping, at least one of the following is true: (Level AAA)
1.4.7轻声或者无背景音:对于这几种预先录制好的只有音频的内容,1)包含主要话语的前景音,2)不是一个音频验证码或者音频logo,3)没有发声,打算主要音乐用来表达,比如唱歌和说唱,那么要至少要符合下列其中一点:(AAA级)

Note: Per the definition of "decibel," background sound that meets this requirement will be approximately four times quieter than the foreground speech content.
注:根据“分贝”的定义,背景音达到这个要求需要比前景话语内容大约安静4倍。

1.4.8 Visual Presentation: For the visual presentation of blocks of text, a mechanism is available to achieve the following: (Level AAA)
1.4.8视觉感知:对于块状的文本,需要提供一种有效的机制来实现下面的要求:(AAA级要求)
  1. Foreground and background colors can be selected by the user.
    用户可以选择前景色和后景色。
  2. Width is no more than 80 characters or glyphs (40 if CJK).
    宽度不能大于80个字符或符号(中、日、韩40个字)
  3. Text is not justified (aligned to both the left and the right margins).
    文本不需要两端对齐(同时将左右两端对齐)
  4. Line spacing (leading) is at least space-and-a-half within paragraphs, and paragraph spacing is at least 1.5 times larger than the line spacing.
    段落中的行间距至少是1.5倍行高,段落间距至少是行间距的1.5倍。
  5. Text can be resized without assistive technology up to 200 percent in a way that does not require the user to scroll horizontally to read a line of text on a full-screen window.
    不使用辅助技术,文本可以调整大小到200%并且在全屏下不需要用户水平滚动去阅读一行文本。
1.4.9 Images of Text (No Exception): Images of text are only used for pure decoration or where a particular presentation of text is essential to the information being conveyed. (Level AAA)
1.4.9图片式文本(没有例外):图片式文本只用于纯装饰或者文字是一个必不可少的传递信息的具体感知方式。(AAA级)

Note: Logotypes (text that is part of a logo or brand name) are considered essential.
注:logo类(logo或者品牌名称的一部分)必须要考虑。

Principle 2: Operable - User interface components and navigation must be operable.
原则2:可操作的——用户界面组件和导航必须是可以操作的。——用户界面组件和导航必须是可以操作的。

Guideline 2.1 Keyboard Accessible: Make all functionality available from a keyboard.
指南2.1 键盘可访问性:让所有功能都能有效的通过键盘操作。

2.1.1 Keyboard: All functionality of the content is operable through a keyboard interface without requiring specific timings for individual keystrokes, except where the underlying function requires input that depends on the path of the user's movement and not just the endpoints. (Level A)
2.1.1键盘:内容的所有功能都可以使用键盘接口操作,不对单个按键有具体的时间要求,除非底层功能需要依赖用户的移动路径而不只是路径的终点来输入。(A级)

Note 1: This exception relates to the underlying function, not the input technique. For example, if using handwriting to enter text, the input technique (handwriting) requires path-dependent input but the underlying function (text input) does not.
注1:上面描述的例外只适用于与底层功能相关的范畴,而不针对输入技术。举个例子:如果使用手写去输入文字,手写需要依赖路径输入,但是底层的功能(文字输入功能)并不需要依赖路径。

Note 2: This does not forbid and should not discourage providing mouse input or other input methods in addition to keyboard operation.
注2:这并不是禁止或者阻止提供鼠标或者其他除键盘以外的输入方法。

2.1.2 No Keyboard Trap: If keyboard focus can be moved to a component of the page using a keyboard interface, then focus can be moved away from that component using only a keyboard interface, and, if it requires more than unmodified arrow or tab keys or other standard exit methods, the user is advised of the method for moving focus away. (Level A)
2.1.2禁止键盘陷阱:如果焦点通过键盘接口聚焦到到页面上的一个组件上,那么焦点只能使用键盘接口才可以离开这个组件,如果需要除原生箭头键或者Tab键以外的其他标准的退出方法,需要将移出焦点的方法传达给用户。(A级)

Note: Since any content that does not meet this success criterion can interfere with a user's ability to use the whole page, all content on the Web page (whether it is used to meet other success criteria or not) must meet this success criterion. See Conformance Requirement 5: Non-Interference.
注:由于任何未能满足此成功标准的内容都会干扰用户使用整个网页,所以网页上的所有内容(无论它是否满足其他的成功标准)都必须实现这个成功标准。参看:一致性要求5:互不干涉。


2.1.3 Keyboard (No Exception): All functionality of the content is operable through a keyboard interface without requiring specific timings for individual keystrokes. (Level AAA)
2.1.3键盘(没有例外):内容的所有功能都可以使用键盘接口操作,不对单个按键有具体的时间要求。(AAA级)

Guideline 2.2 Enough Time: Provide users enough time to read and use content.
指南2.2 充足的时间:要提供给用户足够的时间去阅读和使用内容。

2.2.1 Timing Adjustable: For each time limit that is set by the content, at least one of the following is true: (Level A)
2.2.1可调整时间:每一个为内容设置的时间限制,至少符合下面其中一点:(A级)

Note: This success criterion helps ensure that users can complete tasks without unexpected changes in content or context that are a result of a time limit. This success criterion should be considered in conjunction with Success Criterion 3.2.1, which puts limits on changes of content or context as a result of user action.
注:这个成功标注会帮助保证用户可以完成任务不会由于时间限制出现突然的更改内容或者上下文的结果。这个成功标准应该连同成功标准3.2.1仔细考虑,让修改内容或上下文的限制作为用户操作的结果。

2.2.2 Pause, Stop, Hide: For moving,blinking, scrolling, or auto-updating information, all of the following are true: (Level A)
2.2.2暂停,停止,隐藏:对于移动,闪烁,滚动或者其他自动更新的信息,应该符合一下全部要求:(A级)

Note 1: For requirements related to flickering or flashing content, refer to Guideline 2.3.
注1:关于闪烁和闪光的相关要求可参看指南2.3。

Note 2: Since any content that does not meet this success criterion can interfere with a user's ability to use the whole page, all content on the Web page (whether it is used to meet other success criteria or not) must meet this success criterion. See Conformance Requirement 5: Non-Interference.
注2:由于任何未能满足此成功标准的内容都会干扰用户使用整个网页,所以网页上的所有内容(无论它是否满足其他的成功标准)都必须实现这个成功标准。参看:一致性要求5:互不干涉。

Note 3: Content that is updated periodically by software or that is streamed to the user agent is not required to preserve or present information that is generated or received between the initiation of the pause and resuming presentation, as this may not be technically possible, and in many situations could be misleading to do so.
注3:由软件定期更新的或者传给用户代理不需要请求保存内容,或者在暂停和重新恢复中生成或接收展示的信息,类似这些可能没有技术方案并且在很多情况下可能是误导性的。

Note 4: An animation that occurs as part of a preload phase or similar situation can be considered essential if interaction cannot occur during that phase for all users and if not indicating progress could confuse users or cause them to think that content was frozen or broken.
注4:以作为预加载阶段的一部分或者类似情形的形式出现的动画必须要考虑如果在这个阶段不与用户发生交互并且没有显示进度可能导致用户困惑或者认为内容冻结或者损坏。


2.2.3 No Timing: Timing is not anessential part of the event or activity presented by the content, except for non-interactive synchronized media and real-time events. (Level AAA)
2.2.3不定时:除非是非交互的同步媒体和实时事件,否则定时不应该是展示事件或者活动内容的必不可少的部分。(AAA级)
2.2.4 Interruptions: Interruptions can be postponed or suppressed by the user, except interruptions involving an emergency. (Level AAA)
2.2.4中断:除非中断涉及到一个紧急情况,否则用户可以推迟或者禁止中断。(AAA级)
2.2.5 Re-authenticating: When an authenticated session expires, the user can continue the activity without loss of data after re-authenticating. (Level AAA)
2.2.5重新验证:当一个验证会话失效,在重新验证之后不 应丢失数据,用户可以继续进行活动。(AAA级)

Guideline 2.3 Seizures: Do not design content in a way that is known to cause seizures.
指南2.3 癫痫:不要设计已知的可以导致癫痫发作的内容。

2.3.1 Three Flashes or Below Threshold: Web pages do not contain anything that flashes more than three times in any one second period, or the flash is below the general flash and red flash thresholds. (Level A)
2.3.1三次闪烁或者低于阈值:网页中不要包含任何每秒大于三次或者低于普通和红色闪烁阈值的闪烁。(A级)

Note: Since any content that does not meet this success criterion can interfere with a user's ability to use the whole page, all content on the Web page (whether it is used to meet other success criteria or not) must meet this success criterion. See Conformance Requirement 5: Non-Interference.
注:由于任何未能满足此成功标准的内容都会干扰用户使用整个网页,所以网页上的所有内容(无论它是否满足其他的成功标准)都必须实现这个成功标准。参看:一致性要求5:互不干涉。

2.3.2 Three Flashes: Web pages do not contain anything that flashes more than three times in any one second period. (Level AAA)
2.3.2三次闪烁:网页中不要包含任何每秒大于三次的闪烁(AAA级)
2.4.1 Bypass Blocks: A mechanism is available to bypass blocks of content that are repeated on multiple Web pages. (Level A)
2.4.1跳过区域:需要一种机制可以让用户跳过在多个网页上重复的内容区域。
2.4.2 Page Titled: Web pages have titles that describe topic or purpose. (Level A)
2.4.2页面标题:网页要有一个描述主题或者用途的标题。(A级)
2.4.3 Focus Order: If a Web page can be navigated sequentially and the navigation sequences affect meaning or operation, focusable components receive focus in an order that preserves meaning and operability. (Level A)
2.4.3焦点序列:如果网页可以按顺序导航并且导航顺序影响含义或者操作,可聚焦的组件应在一个可以保护含义和可操作性的序列中接收焦点。(A级)
2.4.4 Link Purpose (In Context): The purpose of each link can be determined from the link text alone or from the link text together with its programmatically determined link context, except where the purpose of the link would be ambiguous to users in general. (Level A)
2.4.4链接用途(在上下文中):仅从链接的文本或者将链接文本和它编程确定的链接上下文关联在一起与就能确定链接的目的,一般来说除非链接的目的是用来迷惑用户。(A级)

2.4.5 Multiple Ways: More than one way is available to locate a Web page within a set of Web pages except where the Web Page is the result of, or a step in, a process. (Level AA)
2.4.5多种方式:在一组网页中有多种方式去有效的定位一个网页,除非网页是一个步骤的结果,或者一个步骤,一个进程。(AA级)
2.4.6 Headings and Labels: Headings and labels describe topic or purpose. (Level AA)
2.4.标题和标签:标题和标签应描述主体或者用途。(AA级)
2.4.7 Focus Visible: Any keyboard operable user interface has a mode of operation where the keyboard focus indicator is visible. (Level AA)
2.4.7可视的焦点:任何键盘操作的用户界面需要一个键盘焦点的指示是可视的操作模式。(AA级)

2.4.8 Location: Information about the user's location within a set of Web pages is available. (Level AAA)
2.4.8定位:一组网页中关于用户定位的信息应该是有效的。(AAA级)
2.4.9 Link Purpose (Link Only): A mechanism is available to allow the purpose of each link to be identified from link text alone, except where the purpose of the link would be ambiguous to users in general. (Level AAA)
2.4.8链接用途(仅链接本身):需要提供一个有效的机制允许仅仅从链接的文本就确定每一个链接的用途,一般来说除非链接的目的就是用来迷惑用户的。(AAA级)
2.4.10 Section Headings: Section headings are used to organize the content. (Level AAA)
2.4.10章节标题:使用章节标题来组织内容。(AAA级)

Note 1: "Heading" is used in its general sense and includes titles and other ways to add a heading to different types of content.
注1:” heading标签”用来标识内容的一般语义,包括标题和其他为不同类型内容添加一个标题的方法。

Note 2: This success criterion covers sections within writing, not user interface components. User Interface components are covered under Success Criterion 4.1.2.
注2:这个成功标准包含章节中写作的部分,不涵盖用户界面组件。成功标准4.1.2涵盖了用户界面组件的信息。

Principle 3: Understandable - Information and the operation of user interface must be understandable.
原则3:可理解的——信息和用户界面的交互必须是可理解的。

Guideline 3.1 Readable: Make text content readable and understandable.
指南3.1 可读的:让文字内容可读并且可理解。

3.1.1 Language of Page: The default human language of each Web page can be programmatically determined. (Level A)
3.1.1页面语言:每个网页默认的人类语言可以由程序来确定。(A级)

3.1.2 Language of Parts: The human language of each passage or phrase in the content can be programmatically determined except for proper names, technical terms, words of indeterminate language, and words or phrases that have become part of the vernacular of the immediately surrounding text. (Level AA)
3.1.2网页中各个部分的语言:内容里的每一段或者每一个短语的人类语言都可以由程序来确定。除了专有名称、技术术语、无法确定语言的词语以及部分紧邻文本周围的方言。(AA级)

3.1.3 Unusual Words: A mechanism is available for identifying specific definitions of words or phrases used in an unusual or restricted way, including idioms and jargon. (Level AAA)
3.1.3非常用词汇:需要有一种有效的机制,来识别非常用或限制级的词语或词组的具体含义,包括成语和难懂的术语。(AAA级)
3.1.4 Abbreviations: A mechanism for identifying the expanded form or meaning of abbreviations is available. (Level AAA)
3.1.4缩写:需要有一种有效机制,来识别缩写的全称或含义。(AAA级)
3.1.5 Reading Level: When text requires reading ability more advanced than the lower secondary education level after removal of proper names and titles, supplemental content, or a version that does not require reading ability more advanced than the lower secondary education level, is available. (Level AAA)
3.1.5阅读级别: 当删除专有名称、标题和补充内容之后的文本还需要高于初中教育水平阅读能力的时候,就要有一个不需要阅读能力高于初中教育水平的版本。(AAA级)
3.1.6 Pronunciation: A mechanism is available for identifying specific pronunciation of words where meaning of the words, in context, is ambiguous without knowing the pronunciation. (Level AAA)
3.1.6发音:当词语在上下文中不知道其发音就会引起歧义时,需要一个机制来识别词语的具体发音。(AAA级)

Guideline 3.2 Predictable: Make Web pages appear and operate in predictable ways.
指南3.2 可预见的:让网页在可预见的方式中呈现和交互。

3.2.1 On Focus: When any component receives focus, it does not initiate a change of context. (Level A)
3.2.1聚焦:任何组件当它接收焦点的时候,不能导致上下文的变化。(A级)
3.2.2 On Input: Changing the setting of any user interface component does not automatically cause a change of context unless the user has been advised of the behavior before using the component. (Level A)
3.2.2输入:除非用户在使用组件之前被告知,否则任何改变用户界面的设置都不应该自动导致上下文的变化。(A级)

3.2.3 Consistent Navigation: Navigational mechanisms that are repeated on multiple Web pages within a set of Web pages occur in the same relative order each time they are repeated, unless a change is initiated by the user. (Level AA)
3.2.3一致的导航:除非用户改变导航机制,否则在一组网页中,多个网页重复出现的时候,他们的相对位置都应该是相同的。(AA级)
3.2.4 Consistent Identification: Components that have the same functionality within a set of Web pages are identified consistently. (Level AA)
3.2.4一致的识别性:在一组网页中相同功能的组件的识别性要一致。(AA级)

3.2.5 Change on Request: Changes of context are initiated only by user request or a mechanism is available to turn off such changes. (Level AAA)
3.2.5应要求改变:只有用户的要求才能导致上下文的改变,或者提供一种关闭上下文改变的有效机制。(AAA级)

Guideline 3.3 Input Assistance: Help users avoid and correct mistakes.
指南3.3 输入帮助:帮助用户避免和纠正错误。

3.3.1 Error Identification: If an input error is automatically detected, the item that is in error is identified and the error is described to the user in text. (Level A)
3.3.1错误识别:如果一个输入错误是可以自动检测的,那么这个项目的错误应被用户发现,并且用文字进行表述。(A级)
3.3.2 Labels or Instructions: Labels or instructions are provided when content requires user input. (Level A)
3.3.2标签或操作说明:当内容需要用户输入的时候,需要提供标签或者操作说明。(A级)

3.3.3 Error Suggestion: If an input error is automatically detected and suggestions for correction are known, then the suggestions are provided to the user, unless it would jeopardize the security or purpose of the content. (Level AA)
3.3.3错误提示:如果可以自动检测输入错误并且提供已知的修改建议,那么除非提示会危害到内容的安全和目的,否则应该将它提供给用户。(AA级)
3.3.4 Error Prevention (Legal, Financial, Data): For Web pages that cause legal commitments or financial transactions for the user to occur, that modify or delete user-controllable data in data storage systems, or that submit user test responses, at least one of the following is true: (Level AA)
3.3.4错误预防(法律、金融、数据):对于用户操作可以引起法律承诺或者金融交易的网页,修改或者删除数据存储系统里用户可操作的数据,或者提交用户验证的响应,至少要遵循以下其中一点:(AA级)
  1. Reversible: Submissions are reversible.
    可逆的:提交是可逆的。
  2. Checked: Data entered by the user is checked for input errors and the user is provided an opportunity to correct them.
    检查:检查用户输入的数据是否有输入错误并且给用户提供一个修改他们的机会。
  3. Confirmed: A mechanism is available for reviewing, confirming, and correcting information before finalizing the submission.
    确认:在最后提交之前,需要提供一个检查、确认和修改信息的有效机制。

3.3.5 Help: Context-sensitive help is available. (Level AAA)
3.3.5帮助:提供上下文相关帮助。(AAA级别)
3.3.6 Error Prevention (All): For Web pages that require the user to submit information, at least one of the following is true: (Level AAA)
3.3.6错误预防(所有):对于需要用户提交的信息的网页,至少要遵循以下其中一点:(AAA级)
  1. Reversible: Submissions are reversible.
    可逆的:提交是可逆的。
  2. Checked: Data entered by the user is checked for input errors and the user is provided an opportunity to correct them.
    检查:检查用户输入的数据是否有输入错误并且给用户提供一个修改他们的机会。
  3. Confirmed: A mechanism is available for reviewing, confirming, and correcting information before finalizing the submission.
    确认:在最后提交之前,需要提供一个检查、确认和修改信息的有效机制。

Principle 4: Robust - Content must be robust enough that it can be interpreted reliably by a wide variety of user agents, including assistive technologies.
原则4:健壮性——内容必须足够健壮,从而能够通过包括辅助技术在内的各种用户代理可靠的进行解释。

Guideline 4.1 Compatible: Maximize compatibility with current and future user agents, including assistive technologies.
指南4.1 兼容性:最大程度的兼容当前和未来的用户代理,包括辅助技术。

4.1.1 Parsing: In content implemented using markup languages, elements have complete start and end tags, elements are nested according to their specifications, elements do not contain duplicate attributes, and any IDs are unique, except where the specifications allow these features. (Level A)
4.1.1 语法解析:使用标记语言来组织内容,元素要有完整的开始和结束标签,要根据他们的规范来嵌套,不能包含重复的属性,除非规范允许,否则任何ID都是唯一的。(A级)

Note: Start and end tags that are missing a critical character in their formation, such as a closing angle bracket or a mismatched attribute value quotation mark are not complete.
注:在开始和结束的标签组成中缺少关键字符,比如:一个右尖括号、属性值不匹配或者双引号不完整。

4.1.2 Name, Role, Value: For all user interface components (including but not limited to: form elements, links and components generated by scripts), the name and role can be programmatically determined; states, properties, and values that can be set by the user can be programmatically set; and notification of changes to these items is available to user agents, including assistive technologies. (Level A)
4.1.2名称、角色、值:对于所有的用户界面组件(包括但不限于:表单元素、链接以及由脚本生成的组件),他们的名称和角色可以通过编程确定;状态、属性和值可以通过编程来设置;这些项目变化的通知对包括辅助技术在内的用户代理应该是可用的。(A级别)

Note: This success criterion is primarily for Web authors who develop or script their own user interface components. For example, standard HTML controls already meet this success criterion when used according to specification.
注:这个成功标准主要是用于自己开发或者编写用户界面组件脚本的作者。举个例子:当根据标准使用HTML控件的时候就已经达到了成功的标准。