問題描述

有沒有辦法檢測一個鍵當前是否在 JavaScript 中被關閉?

Is there a way to detect if a key is currently down in JavaScript?

我知道keydown"事件，但這不是我需要的.按鍵被按下后的一段時間，我希望能夠檢測它是否仍然被按下.

I know about the "keydown" event, but that's not what I need. Some time AFTER the key is pressed, I want to be able to detect if it is still pressed down.

P.S. 最大的問題似乎是在一段時間后鍵開始重復，像惡魔一樣觸發 keydown 和 keyup 事件.希望只有一個簡單的 isKeyDown(key) 函數，但如果沒有，則需要克服/解決這個問題.

P. S. The biggest issue seems to be that after some period of time the key begins to repeat, firing off keydown and keyup events like a fiend. Hopefully there is just a simple isKeyDown(key) function, but if not then this issue will need to be overcome / worked around.

推薦答案

有沒有辦法檢測一個鍵當前是否在 JavaScript 中被關閉?

Is there a way to detect if a key is currently down in JavaScript?

不.唯一的可能是監控每個 keyup 和 keydown 并記住.

Nope. The only possibility is monitoring each keyup and keydown and remembering.

一段時間后，按鍵開始重復，像惡魔一樣觸發 keydown 和 keyup 事件.

after some period of time the key begins to repeat, firing off keydown and keyup events like a fiend.

不應該.你肯定會得到 keypress 重復，并且在許多瀏覽器中你也會得到重復 keydown，但是如果 keyup 重復，這是一個錯誤.

It shouldn't. You'll definitely get keypress repeating, and in many browsers you'll also get repeated keydown, but if keyup repeats, it's a bug.

不幸的是，這不是一個完全聞所未聞的錯誤:在 Linux、Chromium 和 Firefox 上(當它在 GTK+ 下運行時，它在流行的發行版中，如 Ubuntu)都生成重復的 keyup-keypress-keydown 序列握著鑰匙，這與快速敲擊鑰匙的人無法區分.

Unfortunately it is not a completely unheard-of bug: on Linux, Chromium, and Firefox (when it is being run under GTK+, which it is in popular distros such as Ubuntu) both generate repeating keyup-keypress-keydown sequences for held keys, which are impossible to distinguish from someone hammering the key really fast.

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