Text selection is reset after pressing a button in iOS/iPadOS

Problem
The Selection and Range article includes a demo button that should show an alert with the selected text. On desktop environments or non-Apple mobile devices, the demo works correctly. The alert shows the current selected text, while the selection itself is also maintained.

However on iOS/iPadOS devices(iPhone, iPad, ...) the text selection disappears as soon as you press the button and the alert appears with empty text.

I believe this is an issue with iOS/iPadOS Safari, rather than a bug in javascript.info but nevertheless I wonder if anyone could share some insight on why this isn't working as expected. I've tried my best but up to this point could not find any similar troubleshooting anywhere else.

https://user-images.githubusercontent.com/34783801/176479597-5d7d5621-a513-497a-a114-3cd4b2c055f8.MP4

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从 Selection and Range 文章及其演示按钮开始，然后使用提供的示例在 iOS/iPadOS Safari 上复现该行为。将选中的文本和 alert 行为与桌面环境及非 Apple 移动环境进行比较；完成的标准是确定这是 Safari 的限制还是 demo 中的问题，并记录证据或受支持的 workaround。