Bookmarklet to invert colors on a page, but *not* of images and videos. Basically a quick dark-mode hack.

invertColors.js

javascript:(function() {
	function parseColor(str) {
		var match = /^\s*(?:(?:#(?:([0-9a-f])([0-9a-f])([0-9a-f])|([0-9a-f]{2})([0-9a-f]{2})([0-9a-f]{2})))|rgb\(\s*([0-9]+)\s*,\s*([0-9]+)\s*,\s*([0-9]+)\s*\)|rgba\(\s*([0-9]+)\s*,\s*([0-9]+)\s*,\s*([0-9]+)\s*,\s*([0-9]+(?:\.[0-9]*)?|\.[0-9]+)\s*\))\s*$/i.exec(str);
		if (!match) throw new SyntaxError(str);
		if (match[1]) {
			return {
				r: parseInt(match[1], 16) * 17,
				g: parseInt(match[2], 16) * 17,
				b: parseInt(match[3], 16) * 17,
				a: 1.0
			};
		}
		else if (match[4]) {
			return {
				r: parseInt(match[4], 16),
				g: parseInt(match[5], 16),
				b: parseInt(match[6], 16),
				a: 1.0
			};
		}
		else if (match[7]) {
			return {
				r: parseInt(match[7], 10),
				g: parseInt(match[8], 10),
				b: parseInt(match[9], 10),
				a: 1.0
			};
		}
		else if (match[10]) {
			return {
				r: parseInt(match[10], 10),
				g: parseInt(match[11], 10),
				b: parseInt(match[12], 10),
				a: parseFloat(match[13]),
			};
		}
		throw new SyntaxError(str);
	}

	var bg = getComputedStyle(document.body).backgroundColor;
	if (bg) {
		bg = parseColor(bg);
		if (bg.a === 0.0) {
			bg = getComputedStyle(document.documentElement).backgroundColor;
			if (bg) {
				bg = parseColor(bg);
				if (bg.a === 0.0) {
					bg.r = 255;
					bg.g = 255;
					bg.b = 255;
				}
			}
		}
	}
	if (!bg) {
		bg = {r:255, g:255, b:255};
	}
	document.body.style.backgroundColor = 'rgb(' + (255 - bg.r) + ',' + (255 - bg.g) + ',' + (255 - bg.b) + ')';

	var filter = document.body.style.filter;
	if (filter) {
		filter += ',';
	}
	filter += 'invert(100%)';
	document.body.style.filter = filter;

	var style = document.createElement('style');
	style.innerText = ':not(picture) > img,video,picture{filter:invert(100%) !important;}';
	document.body.appendChild(style);
})();void(0)