WASD Scroll hotkeys for websites

Use WASD keys to scroll, not just arrow buttons
当前为 2022-02-07 提交的版本，查看最新版本。
换行
// ==UserScript==
// @name          WASD Scroll hotkeys for websites
// @namespace     wasd_scroll
// @author        Owyn
// @version       1.0
// @description   Use WASD keys to scroll, not just arrow buttons
// @supportURL    https://github.com/Owyn/WASD_Scroll/issues
// @homepage      https://github.com/Owyn/WASD_Scroll
// @run-at        document-end
// @grant         GM_registerMenuCommand
// @include       *
// ==/UserScript==

"use strict";

var by = 70;
var scroll_speed = "auto"; // "smooth" / "instant" / "auto" - same as browser settings

if (typeof GM_registerMenuCommand !== "undefined")
{
	GM_registerMenuCommand("WASD Scroll - Disable (this once)", disable, "w");
}

window.addEventListener("keydown", onkeydown, false); // after all others

if (typeof KeyEvent === "undefined")
{
	var KeyEvent = {
		DOM_VK_A: 65,
		DOM_VK_D: 68,
		DOM_VK_S: 83,
		DOM_VK_W: 87
	};
}

var inputs = ['input', 'select', 'button', 'textarea', 'pre'];

function onkeydown (b)
{
	let a = (window.event) ? b.keyCode : b.which;

	if (b.altKey || b.ctrlKey || b.metaKey)
	{
		return;
	}

	let activeElement = document.activeElement;
    console.warn(activeElement);
	if (activeElement && inputs.indexOf(activeElement.tagName.toLowerCase()) !== -1)
	{
		return;
	}

	switch (a)
	{
	case KeyEvent.DOM_VK_D:
		window.scrollBy({
			top: 0,
			left: by,
			behavior: scroll_speed
		});
		break;
	case KeyEvent.DOM_VK_A:
		window.scrollBy({
			top: 0,
			left: by * -1,
			behavior: scroll_speed
		});
		break;
	case KeyEvent.DOM_VK_W:
		window.scrollBy({
			top: by * -1,
			left: 0,
			behavior: scroll_speed
		});
		break;
	case KeyEvent.DOM_VK_S:
		window.scrollBy({
			top: by,
			left: 0,
			behavior: scroll_speed
		});
		break;
	}
}

function disable()
{
	window.removeEventListener("keydown", onkeydown, false);
	console.warn("WASD Scroll disabled");
}