Add some more random JS

4 files changed, 984 insertions, 0 deletions

diff --git a/assets/js/f1.js b/assets/js/f1.js
index 66eacd8..92e2029 100644
--- a/assets/js/f1.js
+++ b/assets/js/f1.js
@@ -4,3 +4,249 @@ document.writeln('This is ' + getName());
 function getName() {
 	return 'f1';
 }
+
+/*! instant.page v5.1.0 - (C) 2019-2020 Alexandre Dieulot - https://instant.page/license */
+
+let mouseoverTimer;
+let lastTouchTimestamp;
+const prefetches = new Set();
+const prefetchElement = document.createElement('link');
+const isSupported =
+	prefetchElement.relList &&
+	prefetchElement.relList.supports &&
+	prefetchElement.relList.supports('prefetch') &&
+	window.IntersectionObserver &&
+	'isIntersecting' in IntersectionObserverEntry.prototype;
+const allowQueryString = 'instantAllowQueryString' in document.body.dataset;
+const allowExternalLinks = 'instantAllowExternalLinks' in document.body.dataset;
+const useWhitelist = 'instantWhitelist' in document.body.dataset;
+const mousedownShortcut = 'instantMousedownShortcut' in document.body.dataset;
+const DELAY_TO_NOT_BE_CONSIDERED_A_TOUCH_INITIATED_ACTION = 1111;
+
+let delayOnHover = 65;
+let useMousedown = false;
+let useMousedownOnly = false;
+let useViewport = false;
+
+if ('instantIntensity' in document.body.dataset) {
+	const intensity = document.body.dataset.instantIntensity;
+
+	if (intensity.substr(0, 'mousedown'.length) == 'mousedown') {
+		useMousedown = true;
+		if (intensity == 'mousedown-only') {
+			useMousedownOnly = true;
+		}
+	} else if (intensity.substr(0, 'viewport'.length) == 'viewport') {
+		if (
+			!(
+				navigator.connection &&
+				(navigator.connection.saveData ||
+					(navigator.connection.effectiveType && navigator.connection.effectiveType.includes('2g')))
+			)
+		) {
+			if (intensity == 'viewport') {
+				/* Biggest iPhone resolution (which we want): 414 × 896 = 370944
+         * Small 7" tablet resolution (which we don’t want): 600 × 1024 = 614400
+         * Note that the viewport (which we check here) is smaller than the resolution due to the UI’s chrome */
+				if (document.documentElement.clientWidth * document.documentElement.clientHeight < 450000) {
+					useViewport = true;
+				}
+			} else if (intensity == 'viewport-all') {
+				useViewport = true;
+			}
+		}
+	} else {
+		const milliseconds = parseInt(intensity);
+		if (!isNaN(milliseconds)) {
+			delayOnHover = milliseconds;
+		}
+	}
+}
+
+if (isSupported) {
+	const eventListenersOptions = {
+		capture: true,
+		passive: true
+	};
+
+	if (!useMousedownOnly) {
+		document.addEventListener('touchstart', touchstartListener, eventListenersOptions);
+	}
+
+	if (!useMousedown) {
+		document.addEventListener('mouseover', mouseoverListener, eventListenersOptions);
+	} else if (!mousedownShortcut) {
+		document.addEventListener('mousedown', mousedownListener, eventListenersOptions);
+	}
+
+	if (mousedownShortcut) {
+		document.addEventListener('mousedown', mousedownShortcutListener, eventListenersOptions);
+	}
+
+	if (useViewport) {
+		let triggeringFunction;
+		if (window.requestIdleCallback) {
+			triggeringFunction = (callback) => {
+				requestIdleCallback(callback, {
+					timeout: 1500
+				});
+			};
+		} else {
+			triggeringFunction = (callback) => {
+				callback();
+			};
+		}
+
+		triggeringFunction(() => {
+			const intersectionObserver = new IntersectionObserver((entries) => {
+				entries.forEach((entry) => {
+					if (entry.isIntersecting) {
+						const linkElement = entry.target;
+						intersectionObserver.unobserve(linkElement);
+						preload(linkElement.href);
+					}
+				});
+			});
+
+			document.querySelectorAll('a').forEach((linkElement) => {
+				if (isPreloadable(linkElement)) {
+					intersectionObserver.observe(linkElement);
+				}
+			});
+		});
+	}
+}
+
+function touchstartListener(event) {
+	/* Chrome on Android calls mouseover before touchcancel so `lastTouchTimestamp`
+   * must be assigned on touchstart to be measured on mouseover. */
+	lastTouchTimestamp = performance.now();
+
+	const linkElement = event.target.closest('a');
+
+	if (!isPreloadable(linkElement)) {
+		return;
+	}
+
+	preload(linkElement.href);
+}
+
+function mouseoverListener(event) {
+	if (performance.now() - lastTouchTimestamp < DELAY_TO_NOT_BE_CONSIDERED_A_TOUCH_INITIATED_ACTION) {
+		return;
+	}
+
+	const linkElement = event.target.closest('a');
+
+	if (!isPreloadable(linkElement)) {
+		return;
+	}
+
+	linkElement.addEventListener('mouseout', mouseoutListener, { passive: true });
+
+	mouseoverTimer = setTimeout(() => {
+		preload(linkElement.href);
+		mouseoverTimer = undefined;
+	}, delayOnHover);
+}
+
+function mousedownListener(event) {
+	const linkElement = event.target.closest('a');
+
+	if (!isPreloadable(linkElement)) {
+		return;
+	}
+
+	preload(linkElement.href);
+}
+
+function mouseoutListener(event) {
+	if (event.relatedTarget && event.target.closest('a') == event.relatedTarget.closest('a')) {
+		return;
+	}
+
+	if (mouseoverTimer) {
+		clearTimeout(mouseoverTimer);
+		mouseoverTimer = undefined;
+	}
+}
+
+function mousedownShortcutListener(event) {
+	if (performance.now() - lastTouchTimestamp < DELAY_TO_NOT_BE_CONSIDERED_A_TOUCH_INITIATED_ACTION) {
+		return;
+	}
+
+	const linkElement = event.target.closest('a');
+
+	if (event.which > 1 || event.metaKey || event.ctrlKey) {
+		return;
+	}
+
+	if (!linkElement) {
+		return;
+	}
+
+	linkElement.addEventListener(
+		'click',
+		function(event) {
+			if (event.detail == 1337) {
+				return;
+			}
+
+			event.preventDefault();
+		},
+		{ capture: true, passive: false, once: true }
+	);
+
+	const customEvent = new MouseEvent('click', { view: window, bubbles: true, cancelable: false, detail: 1337 });
+	linkElement.dispatchEvent(customEvent);
+}
+
+function isPreloadable(linkElement) {
+	if (!linkElement || !linkElement.href) {
+		return;
+	}
+
+	if (useWhitelist && !('instant' in linkElement.dataset)) {
+		return;
+	}
+
+	if (!allowExternalLinks && linkElement.origin != location.origin && !('instant' in linkElement.dataset)) {
+		return;
+	}
+
+	if (![ 'http:', 'https:' ].includes(linkElement.protocol)) {
+		return;
+	}
+
+	if (linkElement.protocol == 'http:' && location.protocol == 'https:') {
+		return;
+	}
+
+	if (!allowQueryString && linkElement.search && !('instant' in linkElement.dataset)) {
+		return;
+	}
+
+	if (linkElement.hash && linkElement.pathname + linkElement.search == location.pathname + location.search) {
+		return;
+	}
+
+	if ('noInstant' in linkElement.dataset) {
+		return;
+	}
+
+	return true;
+}
+
+function preload(url) {
+	if (prefetches.has(url)) {
+		return;
+	}
+
+	const prefetcher = document.createElement('link');
+	prefetcher.rel = 'prefetch';
+	prefetcher.href = url;
+	document.head.appendChild(prefetcher);
+
+	prefetches.add(url);
+}
diff --git a/assets/js/f2.js b/assets/js/f2.js
index 2c93505..1df8874 100644
--- a/assets/js/f2.js
+++ b/assets/js/f2.js
@@ -4,3 +4,249 @@ document.writeln('This is ' + getName());
 function getName() {
 	return 'f2';
 }
+
+/*! instant.page v5.1.0 - (C) 2019-2020 Alexandre Dieulot - https://instant.page/license */
+
+let mouseoverTimer;
+let lastTouchTimestamp;
+const prefetches = new Set();
+const prefetchElement = document.createElement('link');
+const isSupported =
+	prefetchElement.relList &&
+	prefetchElement.relList.supports &&
+	prefetchElement.relList.supports('prefetch') &&
+	window.IntersectionObserver &&
+	'isIntersecting' in IntersectionObserverEntry.prototype;
+const allowQueryString = 'instantAllowQueryString' in document.body.dataset;
+const allowExternalLinks = 'instantAllowExternalLinks' in document.body.dataset;
+const useWhitelist = 'instantWhitelist' in document.body.dataset;
+const mousedownShortcut = 'instantMousedownShortcut' in document.body.dataset;
+const DELAY_TO_NOT_BE_CONSIDERED_A_TOUCH_INITIATED_ACTION = 1111;
+
+let delayOnHover = 65;
+let useMousedown = false;
+let useMousedownOnly = false;
+let useViewport = false;
+
+if ('instantIntensity' in document.body.dataset) {
+	const intensity = document.body.dataset.instantIntensity;
+
+	if (intensity.substr(0, 'mousedown'.length) == 'mousedown') {
+		useMousedown = true;
+		if (intensity == 'mousedown-only') {
+			useMousedownOnly = true;
+		}
+	} else if (intensity.substr(0, 'viewport'.length) == 'viewport') {
+		if (
+			!(
+				navigator.connection &&
+				(navigator.connection.saveData ||
+					(navigator.connection.effectiveType && navigator.connection.effectiveType.includes('2g')))
+			)
+		) {
+			if (intensity == 'viewport') {
+				/* Biggest iPhone resolution (which we want): 414 × 896 = 370944
+         * Small 7" tablet resolution (which we don’t want): 600 × 1024 = 614400
+         * Note that the viewport (which we check here) is smaller than the resolution due to the UI’s chrome */
+				if (document.documentElement.clientWidth * document.documentElement.clientHeight < 450000) {
+					useViewport = true;
+				}
+			} else if (intensity == 'viewport-all') {
+				useViewport = true;
+			}
+		}
+	} else {
+		const milliseconds = parseInt(intensity);
+		if (!isNaN(milliseconds)) {
+			delayOnHover = milliseconds;
+		}
+	}
+}
+
+if (isSupported) {
+	const eventListenersOptions = {
+		capture: true,
+		passive: true
+	};
+
+	if (!useMousedownOnly) {
+		document.addEventListener('touchstart', touchstartListener, eventListenersOptions);
+	}
+
+	if (!useMousedown) {
+		document.addEventListener('mouseover', mouseoverListener, eventListenersOptions);
+	} else if (!mousedownShortcut) {
+		document.addEventListener('mousedown', mousedownListener, eventListenersOptions);
+	}
+
+	if (mousedownShortcut) {
+		document.addEventListener('mousedown', mousedownShortcutListener, eventListenersOptions);
+	}
+
+	if (useViewport) {
+		let triggeringFunction;
+		if (window.requestIdleCallback) {
+			triggeringFunction = (callback) => {
+				requestIdleCallback(callback, {
+					timeout: 1500
+				});
+			};
+		} else {
+			triggeringFunction = (callback) => {
+				callback();
+			};
+		}
+
+		triggeringFunction(() => {
+			const intersectionObserver = new IntersectionObserver((entries) => {
+				entries.forEach((entry) => {
+					if (entry.isIntersecting) {
+						const linkElement = entry.target;
+						intersectionObserver.unobserve(linkElement);
+						preload(linkElement.href);
+					}
+				});
+			});
+
+			document.querySelectorAll('a').forEach((linkElement) => {
+				if (isPreloadable(linkElement)) {
+					intersectionObserver.observe(linkElement);
+				}
+			});
+		});
+	}
+}
+
+function touchstartListener(event) {
+	/* Chrome on Android calls mouseover before touchcancel so `lastTouchTimestamp`
+   * must be assigned on touchstart to be measured on mouseover. */
+	lastTouchTimestamp = performance.now();
+
+	const linkElement = event.target.closest('a');
+
+	if (!isPreloadable(linkElement)) {
+		return;
+	}
+
+	preload(linkElement.href);
+}
+
+function mouseoverListener(event) {
+	if (performance.now() - lastTouchTimestamp < DELAY_TO_NOT_BE_CONSIDERED_A_TOUCH_INITIATED_ACTION) {
+		return;
+	}
+
+	const linkElement = event.target.closest('a');
+
+	if (!isPreloadable(linkElement)) {
+		return;
+	}
+
+	linkElement.addEventListener('mouseout', mouseoutListener, { passive: true });
+
+	mouseoverTimer = setTimeout(() => {
+		preload(linkElement.href);
+		mouseoverTimer = undefined;
+	}, delayOnHover);
+}
+
+function mousedownListener(event) {
+	const linkElement = event.target.closest('a');
+
+	if (!isPreloadable(linkElement)) {
+		return;
+	}
+
+	preload(linkElement.href);
+}
+
+function mouseoutListener(event) {
+	if (event.relatedTarget && event.target.closest('a') == event.relatedTarget.closest('a')) {
+		return;
+	}
+
+	if (mouseoverTimer) {
+		clearTimeout(mouseoverTimer);
+		mouseoverTimer = undefined;
+	}
+}
+
+function mousedownShortcutListener(event) {
+	if (performance.now() - lastTouchTimestamp < DELAY_TO_NOT_BE_CONSIDERED_A_TOUCH_INITIATED_ACTION) {
+		return;
+	}
+
+	const linkElement = event.target.closest('a');
+
+	if (event.which > 1 || event.metaKey || event.ctrlKey) {
+		return;
+	}
+
+	if (!linkElement) {
+		return;
+	}
+
+	linkElement.addEventListener(
+		'click',
+		function(event) {
+			if (event.detail == 1337) {
+				return;
+			}
+
+			event.preventDefault();
+		},
+		{ capture: true, passive: false, once: true }
+	);
+
+	const customEvent = new MouseEvent('click', { view: window, bubbles: true, cancelable: false, detail: 1337 });
+	linkElement.dispatchEvent(customEvent);
+}
+
+function isPreloadable(linkElement) {
+	if (!linkElement || !linkElement.href) {
+		return;
+	}
+
+	if (useWhitelist && !('instant' in linkElement.dataset)) {
+		return;
+	}
+
+	if (!allowExternalLinks && linkElement.origin != location.origin && !('instant' in linkElement.dataset)) {
+		return;
+	}
+
+	if (![ 'http:', 'https:' ].includes(linkElement.protocol)) {
+		return;
+	}
+
+	if (linkElement.protocol == 'http:' && location.protocol == 'https:') {
+		return;
+	}
+
+	if (!allowQueryString && linkElement.search && !('instant' in linkElement.dataset)) {
+		return;
+	}
+
+	if (linkElement.hash && linkElement.pathname + linkElement.search == location.pathname + location.search) {
+		return;
+	}
+
+	if ('noInstant' in linkElement.dataset) {
+		return;
+	}
+
+	return true;
+}
+
+function preload(url) {
+	if (prefetches.has(url)) {
+		return;
+	}
+
+	const prefetcher = document.createElement('link');
+	prefetcher.rel = 'prefetch';
+	prefetcher.href = url;
+	document.head.appendChild(prefetcher);
+
+	prefetches.add(url);
+}
diff --git a/assets/js/f3.js b/assets/js/f3.js
index 6cb4698..c830eda 100644
--- a/assets/js/f3.js
+++ b/assets/js/f3.js
@@ -4,3 +4,249 @@ document.writeln('This is ' + getName());
 function getName() {
 	return 'f3';
 }
+
+/*! instant.page v5.1.0 - (C) 2019-2020 Alexandre Dieulot - https://instant.page/license */
+
+let mouseoverTimer;
+let lastTouchTimestamp;
+const prefetches = new Set();
+const prefetchElement = document.createElement('link');
+const isSupported =
+	prefetchElement.relList &&
+	prefetchElement.relList.supports &&
+	prefetchElement.relList.supports('prefetch') &&
+	window.IntersectionObserver &&
+	'isIntersecting' in IntersectionObserverEntry.prototype;
+const allowQueryString = 'instantAllowQueryString' in document.body.dataset;
+const allowExternalLinks = 'instantAllowExternalLinks' in document.body.dataset;
+const useWhitelist = 'instantWhitelist' in document.body.dataset;
+const mousedownShortcut = 'instantMousedownShortcut' in document.body.dataset;
+const DELAY_TO_NOT_BE_CONSIDERED_A_TOUCH_INITIATED_ACTION = 1111;
+
+let delayOnHover = 65;
+let useMousedown = false;
+let useMousedownOnly = false;
+let useViewport = false;
+
+if ('instantIntensity' in document.body.dataset) {
+	const intensity = document.body.dataset.instantIntensity;
+
+	if (intensity.substr(0, 'mousedown'.length) == 'mousedown') {
+		useMousedown = true;
+		if (intensity == 'mousedown-only') {
+			useMousedownOnly = true;
+		}
+	} else if (intensity.substr(0, 'viewport'.length) == 'viewport') {
+		if (
+			!(
+				navigator.connection &&
+				(navigator.connection.saveData ||
+					(navigator.connection.effectiveType && navigator.connection.effectiveType.includes('2g')))
+			)
+		) {
+			if (intensity == 'viewport') {
+				/* Biggest iPhone resolution (which we want): 414 × 896 = 370944
+         * Small 7" tablet resolution (which we don’t want): 600 × 1024 = 614400
+         * Note that the viewport (which we check here) is smaller than the resolution due to the UI’s chrome */
+				if (document.documentElement.clientWidth * document.documentElement.clientHeight < 450000) {
+					useViewport = true;
+				}
+			} else if (intensity == 'viewport-all') {
+				useViewport = true;
+			}
+		}
+	} else {
+		const milliseconds = parseInt(intensity);
+		if (!isNaN(milliseconds)) {
+			delayOnHover = milliseconds;
+		}
+	}
+}
+
+if (isSupported) {
+	const eventListenersOptions = {
+		capture: true,
+		passive: true
+	};
+
+	if (!useMousedownOnly) {
+		document.addEventListener('touchstart', touchstartListener, eventListenersOptions);
+	}
+
+	if (!useMousedown) {
+		document.addEventListener('mouseover', mouseoverListener, eventListenersOptions);
+	} else if (!mousedownShortcut) {
+		document.addEventListener('mousedown', mousedownListener, eventListenersOptions);
+	}
+
+	if (mousedownShortcut) {
+		document.addEventListener('mousedown', mousedownShortcutListener, eventListenersOptions);
+	}
+
+	if (useViewport) {
+		let triggeringFunction;
+		if (window.requestIdleCallback) {
+			triggeringFunction = (callback) => {
+				requestIdleCallback(callback, {
+					timeout: 1500
+				});
+			};
+		} else {
+			triggeringFunction = (callback) => {
+				callback();
+			};
+		}
+
+		triggeringFunction(() => {
+			const intersectionObserver = new IntersectionObserver((entries) => {
+				entries.forEach((entry) => {
+					if (entry.isIntersecting) {
+						const linkElement = entry.target;
+						intersectionObserver.unobserve(linkElement);
+						preload(linkElement.href);
+					}
+				});
+			});
+
+			document.querySelectorAll('a').forEach((linkElement) => {
+				if (isPreloadable(linkElement)) {
+					intersectionObserver.observe(linkElement);
+				}
+			});
+		});
+	}
+}
+
+function touchstartListener(event) {
+	/* Chrome on Android calls mouseover before touchcancel so `lastTouchTimestamp`
+   * must be assigned on touchstart to be measured on mouseover. */
+	lastTouchTimestamp = performance.now();
+
+	const linkElement = event.target.closest('a');
+
+	if (!isPreloadable(linkElement)) {
+		return;
+	}
+
+	preload(linkElement.href);
+}
+
+function mouseoverListener(event) {
+	if (performance.now() - lastTouchTimestamp < DELAY_TO_NOT_BE_CONSIDERED_A_TOUCH_INITIATED_ACTION) {
+		return;
+	}
+
+	const linkElement = event.target.closest('a');
+
+	if (!isPreloadable(linkElement)) {
+		return;
+	}
+
+	linkElement.addEventListener('mouseout', mouseoutListener, { passive: true });
+
+	mouseoverTimer = setTimeout(() => {
+		preload(linkElement.href);
+		mouseoverTimer = undefined;
+	}, delayOnHover);
+}
+
+function mousedownListener(event) {
+	const linkElement = event.target.closest('a');
+
+	if (!isPreloadable(linkElement)) {
+		return;
+	}
+
+	preload(linkElement.href);
+}
+
+function mouseoutListener(event) {
+	if (event.relatedTarget && event.target.closest('a') == event.relatedTarget.closest('a')) {
+		return;
+	}
+
+	if (mouseoverTimer) {
+		clearTimeout(mouseoverTimer);
+		mouseoverTimer = undefined;
+	}
+}
+
+function mousedownShortcutListener(event) {
+	if (performance.now() - lastTouchTimestamp < DELAY_TO_NOT_BE_CONSIDERED_A_TOUCH_INITIATED_ACTION) {
+		return;
+	}
+
+	const linkElement = event.target.closest('a');
+
+	if (event.which > 1 || event.metaKey || event.ctrlKey) {
+		return;
+	}
+
+	if (!linkElement) {
+		return;
+	}
+
+	linkElement.addEventListener(
+		'click',
+		function(event) {
+			if (event.detail == 1337) {
+				return;
+			}
+
+			event.preventDefault();
+		},
+		{ capture: true, passive: false, once: true }
+	);
+
+	const customEvent = new MouseEvent('click', { view: window, bubbles: true, cancelable: false, detail: 1337 });
+	linkElement.dispatchEvent(customEvent);
+}
+
+function isPreloadable(linkElement) {
+	if (!linkElement || !linkElement.href) {
+		return;
+	}
+
+	if (useWhitelist && !('instant' in linkElement.dataset)) {
+		return;
+	}
+
+	if (!allowExternalLinks && linkElement.origin != location.origin && !('instant' in linkElement.dataset)) {
+		return;
+	}
+
+	if (![ 'http:', 'https:' ].includes(linkElement.protocol)) {
+		return;
+	}
+
+	if (linkElement.protocol == 'http:' && location.protocol == 'https:') {
+		return;
+	}
+
+	if (!allowQueryString && linkElement.search && !('instant' in linkElement.dataset)) {
+		return;
+	}
+
+	if (linkElement.hash && linkElement.pathname + linkElement.search == location.pathname + location.search) {
+		return;
+	}
+
+	if ('noInstant' in linkElement.dataset) {
+		return;
+	}
+
+	return true;
+}
+
+function preload(url) {
+	if (prefetches.has(url)) {
+		return;
+	}
+
+	const prefetcher = document.createElement('link');
+	prefetcher.rel = 'prefetch';
+	prefetcher.href = url;
+	document.head.appendChild(prefetcher);
+
+	prefetches.add(url);
+}
diff --git a/assets/js/f4.js b/assets/js/f4.js
index ef429ac..c26bcb6 100644
--- a/assets/js/f4.js
+++ b/assets/js/f4.js
@@ -4,3 +4,249 @@ document.writeln('This is ' + getName());
 function getName() {
 	return 'f4';
 }
+
+/*! instant.page v5.1.0 - (C) 2019-2020 Alexandre Dieulot - https://instant.page/license */
+
+let mouseoverTimer;
+let lastTouchTimestamp;
+const prefetches = new Set();
+const prefetchElement = document.createElement('link');
+const isSupported =
+	prefetchElement.relList &&
+	prefetchElement.relList.supports &&
+	prefetchElement.relList.supports('prefetch') &&
+	window.IntersectionObserver &&
+	'isIntersecting' in IntersectionObserverEntry.prototype;
+const allowQueryString = 'instantAllowQueryString' in document.body.dataset;
+const allowExternalLinks = 'instantAllowExternalLinks' in document.body.dataset;
+const useWhitelist = 'instantWhitelist' in document.body.dataset;
+const mousedownShortcut = 'instantMousedownShortcut' in document.body.dataset;
+const DELAY_TO_NOT_BE_CONSIDERED_A_TOUCH_INITIATED_ACTION = 1111;
+
+let delayOnHover = 65;
+let useMousedown = false;
+let useMousedownOnly = false;
+let useViewport = false;
+
+if ('instantIntensity' in document.body.dataset) {
+	const intensity = document.body.dataset.instantIntensity;
+
+	if (intensity.substr(0, 'mousedown'.length) == 'mousedown') {
+		useMousedown = true;
+		if (intensity == 'mousedown-only') {
+			useMousedownOnly = true;
+		}
+	} else if (intensity.substr(0, 'viewport'.length) == 'viewport') {
+		if (
+			!(
+				navigator.connection &&
+				(navigator.connection.saveData ||
+					(navigator.connection.effectiveType && navigator.connection.effectiveType.includes('2g')))
+			)
+		) {
+			if (intensity == 'viewport') {
+				/* Biggest iPhone resolution (which we want): 414 × 896 = 370944
+         * Small 7" tablet resolution (which we don’t want): 600 × 1024 = 614400
+         * Note that the viewport (which we check here) is smaller than the resolution due to the UI’s chrome */
+				if (document.documentElement.clientWidth * document.documentElement.clientHeight < 450000) {
+					useViewport = true;
+				}
+			} else if (intensity == 'viewport-all') {
+				useViewport = true;
+			}
+		}
+	} else {
+		const milliseconds = parseInt(intensity);
+		if (!isNaN(milliseconds)) {
+			delayOnHover = milliseconds;
+		}
+	}
+}
+
+if (isSupported) {
+	const eventListenersOptions = {
+		capture: true,
+		passive: true
+	};
+
+	if (!useMousedownOnly) {
+		document.addEventListener('touchstart', touchstartListener, eventListenersOptions);
+	}
+
+	if (!useMousedown) {
+		document.addEventListener('mouseover', mouseoverListener, eventListenersOptions);
+	} else if (!mousedownShortcut) {
+		document.addEventListener('mousedown', mousedownListener, eventListenersOptions);
+	}
+
+	if (mousedownShortcut) {
+		document.addEventListener('mousedown', mousedownShortcutListener, eventListenersOptions);
+	}
+
+	if (useViewport) {
+		let triggeringFunction;
+		if (window.requestIdleCallback) {
+			triggeringFunction = (callback) => {
+				requestIdleCallback(callback, {
+					timeout: 1500
+				});
+			};
+		} else {
+			triggeringFunction = (callback) => {
+				callback();
+			};
+		}
+
+		triggeringFunction(() => {
+			const intersectionObserver = new IntersectionObserver((entries) => {
+				entries.forEach((entry) => {
+					if (entry.isIntersecting) {
+						const linkElement = entry.target;
+						intersectionObserver.unobserve(linkElement);
+						preload(linkElement.href);
+					}
+				});
+			});
+
+			document.querySelectorAll('a').forEach((linkElement) => {
+				if (isPreloadable(linkElement)) {
+					intersectionObserver.observe(linkElement);
+				}
+			});
+		});
+	}
+}
+
+function touchstartListener(event) {
+	/* Chrome on Android calls mouseover before touchcancel so `lastTouchTimestamp`
+   * must be assigned on touchstart to be measured on mouseover. */
+	lastTouchTimestamp = performance.now();
+
+	const linkElement = event.target.closest('a');
+
+	if (!isPreloadable(linkElement)) {
+		return;
+	}
+
+	preload(linkElement.href);
+}
+
+function mouseoverListener(event) {
+	if (performance.now() - lastTouchTimestamp < DELAY_TO_NOT_BE_CONSIDERED_A_TOUCH_INITIATED_ACTION) {
+		return;
+	}
+
+	const linkElement = event.target.closest('a');
+
+	if (!isPreloadable(linkElement)) {
+		return;
+	}
+
+	linkElement.addEventListener('mouseout', mouseoutListener, { passive: true });
+
+	mouseoverTimer = setTimeout(() => {
+		preload(linkElement.href);
+		mouseoverTimer = undefined;
+	}, delayOnHover);
+}
+
+function mousedownListener(event) {
+	const linkElement = event.target.closest('a');
+
+	if (!isPreloadable(linkElement)) {
+		return;
+	}
+
+	preload(linkElement.href);
+}
+
+function mouseoutListener(event) {
+	if (event.relatedTarget && event.target.closest('a') == event.relatedTarget.closest('a')) {
+		return;
+	}
+
+	if (mouseoverTimer) {
+		clearTimeout(mouseoverTimer);
+		mouseoverTimer = undefined;
+	}
+}
+
+function mousedownShortcutListener(event) {
+	if (performance.now() - lastTouchTimestamp < DELAY_TO_NOT_BE_CONSIDERED_A_TOUCH_INITIATED_ACTION) {
+		return;
+	}
+
+	const linkElement = event.target.closest('a');
+
+	if (event.which > 1 || event.metaKey || event.ctrlKey) {
+		return;
+	}
+
+	if (!linkElement) {
+		return;
+	}
+
+	linkElement.addEventListener(
+		'click',
+		function(event) {
+			if (event.detail == 1337) {
+				return;
+			}
+
+			event.preventDefault();
+		},
+		{ capture: true, passive: false, once: true }
+	);
+
+	const customEvent = new MouseEvent('click', { view: window, bubbles: true, cancelable: false, detail: 1337 });
+	linkElement.dispatchEvent(customEvent);
+}
+
+function isPreloadable(linkElement) {
+	if (!linkElement || !linkElement.href) {
+		return;
+	}
+
+	if (useWhitelist && !('instant' in linkElement.dataset)) {
+		return;
+	}
+
+	if (!allowExternalLinks && linkElement.origin != location.origin && !('instant' in linkElement.dataset)) {
+		return;
+	}
+
+	if (![ 'http:', 'https:' ].includes(linkElement.protocol)) {
+		return;
+	}
+
+	if (linkElement.protocol == 'http:' && location.protocol == 'https:') {
+		return;
+	}
+
+	if (!allowQueryString && linkElement.search && !('instant' in linkElement.dataset)) {
+		return;
+	}
+
+	if (linkElement.hash && linkElement.pathname + linkElement.search == location.pathname + location.search) {
+		return;
+	}
+
+	if ('noInstant' in linkElement.dataset) {
+		return;
+	}
+
+	return true;
+}
+
+function preload(url) {
+	if (prefetches.has(url)) {
+		return;
+	}
+
+	const prefetcher = document.createElement('link');
+	prefetcher.rel = 'prefetch';
+	prefetcher.href = url;
+	document.head.appendChild(prefetcher);
+
+	prefetches.add(url);
+}