Accessibility Checklists
The Web Content Accessibility Guidelines (WCAG) 2.提供关于呈现可访问内容的标准的详细信息.
根据WCAG的规定，网页内容应遵循以下原则:
- 一定是 可感知的, either alone or through assistive technology.
- 一定是 可操作的 by all individuals, including those who use assistive technologies or have visual, 听力, motor or other impairments.
- 一定是 readable and understandable, and the website should operate in predictable ways.
- 一定是 健壮的、 even when accessed through a variety of assistive technologies.
万维网联盟(W3C)发布了详细的Web内容可访问性指南 (WCAG) 2.1 that outline how websites can meet each of these principles.
下面列出了一些常见的网站易访问性问题. 全球网赌十大网站建议您在检查网站是否符合可访问性时查阅此列表.
Language Declaration
每个网页都必须在HTML中声明一个默认的语言属性.g., or more specifically . 这些信息有助于搜索引擎返回特定于语言的结果，屏幕阅读器也使用这些信息来切换语言配置文件以提供正确的口音和发音. Learn more about the webpage language declaration.
网页标题
All webpages must have unique page titles. The page title is shown in browser tabs or windows, shown in search engine results, used in page bookmarks/favorites and read aloud by screen readers.
The title tag is an HTML element that specifies the title of a webpage in the
section of HTML, e.g.,Image Alternate Text
替代文本(alt文本)提供了可以在图像中看到的内容的描述. 替代文本应该是有意义和描述性的，以便使用屏幕阅读器和其他辅助技术的视障人士能够理解，他们看不到图像, but need to know its meaning or purpose. The alt text is read aloud by screen readers. Learn more about alternate text descriptions for images.
使用WAVE等工具的自动辅助功能扫描可以告诉您是否所有文本都丢失了, but to determine if the alternate text is appropriate, you need to see the image and judge it in context. Simply using "pic," "myphoto," "img7865," 等. 作为Alt文本将通过自动测试，但不通过手动审查.
像Google这样的搜索引擎也会根据在alternate text属性中找到的内容对图像进行索引.
请注意: 使用相同链接或以下链接中重复链接文本的alt文本会导致屏幕阅读器口吃，因为相同的文本被读出两次. Avoid this kind of duplication when writing alt text descriptions.
标题1 & Properly Structured Headings
All webpages should have a 标题1 or
. 这也会影响SEO，因为像Google这样的搜索引擎会在搜索中使用这些信息. There is only one per page. After an tag, pages should have a proper hierarchy of heading tags with tags appearing below a single , appearing below an , and an appearing below an . 无序的标题被标记为可访问性错误. 像WAVE这样的辅助工具可以识别页面上的所有标题. Learn more about structuring webpages with headings.
Skip Links "Skip to Main Content"
tag, pages should have a proper hierarchy of heading tags with tags appearing below a single , appearing below an , and an appearing below an . 无序的标题被标记为可访问性错误. 像WAVE这样的辅助工具可以识别页面上的所有标题. Learn more about structuring webpages with headings.
Skip Links "Skip to Main Content"
, appearing below an , and an appearing below an . 无序的标题被标记为可访问性错误. 像WAVE这样的辅助工具可以识别页面上的所有标题. Learn more about structuring webpages with headings.
Skip Links "Skip to Main Content"
, and an appearing below an . 无序的标题被标记为可访问性错误. 像WAVE这样的辅助工具可以识别页面上的所有标题. Learn more about structuring webpages with headings.
Skip Links "Skip to Main Content"
. 无序的标题被标记为可访问性错误. 像WAVE这样的辅助工具可以识别页面上的所有标题. Learn more about structuring webpages with headings.
Skip Links "Skip to Main Content"
像“跳到主要内容”这样的链接允许使用屏幕阅读器的访问者跳过网页上多余的内容, e.g., skip over the navigation to access the main content of a page. This feature should be present and working on all webpages. Learn more about bypass blocks and skip to links.
Keyboard Navigation
所有网页及其内容必须完全可导航和操作使用 keyboard controls and shortcuts. 这包括访问页面上的所有导航链接和内容以及下拉菜单中的链接, 表单字段, 等. Learn more about navigating a website with keyboard controls.
Focus Indicators
Focus Indicators 网页上的互动元素在屏幕上是否有清晰的亮点或轮廓, including links, 按钮, 表单字段, 工具提示, 等. For any element on a page that you can interact with using a mouse, 您还应该能够使用键盘来执行相同的操作，并且这种交互应该显示可见的焦点.
表单标签
所有表单字段都必须有相应的标签，并且表单提交错误必须清晰且可访问. 没有相应标签的表单字段不会提供说明字段用途的说明. Learn more about providing proper form labels and instructions.
Avoid Displaying Text in Images
Use CSS to style text separate from an image. 将文字作为图像的一部分不仅会给视障人士带来问题, 但那些使用屏幕放大镜浏览网页的人，以及那些有阅读障碍或其他认知障碍的人. 学习如何 avoid displaying images as text.
表
表 are used for the display of tabular data. Content in data cells is associated with headers and rows. Data table captions and summaries are used where appropriate. 学习如何 create accessible tables.
Video Captions
All prerecorded videos must have captions 在它们出现在勒努瓦-莱恩网站或相关的社交媒体网站之前，e.g., Facebook, Twitter, Instagram, YouTube, Vimeo, 等.
Audio Transcripts
所有发布 audio files must have a text transcript available for the 听力 impaired. This includes transcripts for audio podcasts.
Avoid Using Nondescriptive Links
Link prompts like "点击这里,”“在这里,阅读更多,“了解更多”和其他类似的链接不够描述性，因为所有链接都是由屏幕阅读器大声朗读的，没有上下文. 应该避免这种类型的链接，因为它们被标记为可访问性错误. For example, instead of saying, "to register for the event, 点击这里," use more descriptive links like”,访问 our calendar to buy tickets for this performance. Learn more about the link purpose requirement.
Avoid Displaying URLs in Text
避免在网页中以文本形式发布URL，因为这些URL链接会被屏幕阅读器大声读出. 例如，与其说，“访问招生和经济援助 http://a39tc.cgicalendars.com/admission 要获取更多信息，“你应该将描述性的单词或短语，例如.g.”,访问 全球赌博十大网站 and 金融援助 to request more information." 学习如何 avoid posting URLs as links.
对比 & Color
对于网页和文档附件，文本和背景之间必须有足够的对比. Most text should have a contrast ratio no less than 4.5:1, 大型文字(大于18点或加粗14点)的对比度不小于3:1. 具有背景图像的元素必须定义背景颜色，以便在图像被禁用或不可用时提供足够的对比度.
如果没有任何视觉障碍的人发现由于对比度差而难以查看文件, 对于那些有弱视或色盲等视觉障碍的人来说，这份文件很可能也很难看到.
File Attachments & 文档
All PDFs, Microsoft Office documents (Word, Excel, PowerPoint, 等.) also must comply with accessibility requirements. 最新版本的Microsoft Office for Windows和Mac都有内置的辅助功能检查器.
adobeacrobatdc有一个内置的辅助功能检查器和辅助功能报告工具. 下面列出了在评估PDF文件中的可访问性遵从性时要查找的常见检查点.
- All document properties are populated
- Document title is selected for display
- English is set as the language
- 所有的图像都有替代的文字描述，纯粹的装饰元素是隐藏的
- Document is properly tagged throughout
- A logical reading order is specified
- Proper headings are applied throughout the document
- A manual check is done for possible contrast issues
No scanned documents should ever be posted to the website, i.e., documents scanned from a photocopier or output/printed as a PDF. Files should be saved as PDF files from the original source file. If you only have a scanned version of a document, such as an archival document, 那么在adobeacrobatdc中必须使用光学字符识别或OCR以及上述其他可访问性要求. 了解 document accessibility.
Accessibility Checklists