modal-dialog - 关于何时打开覆盖/模式对话框，是否有任何元素应成为焦点的 Web 可访问性规则？

Question

我见过几种行为:

1. 没有焦点元素。
2. 关闭图标(通常位于叠加层的右上角)已获得焦点。
3. 叠加层内的其他一些元素被聚焦。

如果符合 ADA/ARIA 标准，是否应该关注任何元素？

Answer 1

当前的推荐行为是focus the first focusable element在对话框中。然而，有一些debate on that implementation最近因为它给使用 screen magnification software and screen readers 的用户带来了问题.

in cases where the focus on display moves to a control at the bottom of the dialog a few negative things happen:

1. For a screen magnifier user the focus moves to the control, due to the viewport containing only a small portion of the dialog content (typical magnifcation 400-600%) only the bottom part of the content is viewed, unlike the top of the dialog, the bottom content offers no context. users have to navigate around to get an idea of what is going on.
2. For an SR user (such as JAWS) only the content of the focused element is announced, users have to navigate around the content to get an idea of what is going on.

争论似乎没有解决，但共识正在朝着 new recommendation 方向发展:

1. 如果对话框中的任何元素具有 autofocus 元素，则聚焦该元素。
2. 否则使用 tabindex=-1 和 outline: none 聚焦对话框本身。

聚焦对话框元素本身允许屏幕阅读器向用户阅读对话框的内容，立即为他们提供上下文，屏幕放大镜将在对话框的左上角开始，以便他们可以从开始。