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Custom X and Y scrollbars with drag-to-seek, visible on hover and scroll, no width impact, cross-browser support
// ==UserScript==
// @name Overlay Custom Scrollbar
// @namespace http://tampermonkey.net/
// @version 2.2
// @description Custom X and Y scrollbars with drag-to-seek, visible on hover and scroll, no width impact, cross-browser support
// @license MIT
// @author Grok and Claude
// @match *://*/*
// @grant none
// ==/UserScript==
(function() {
'use strict';
// Add CSS styles
const style = document.createElement('style');
style.textContent = `
/* Hide native scrollbars */
html {
-ms-overflow-style: none !important; /* Edge/IE */
scrollbar-width: none !important; /* Firefox */
overflow: scroll; /* Enable X and Y scrolling */
}
html::-webkit-scrollbar, body::-webkit-scrollbar {
display: none !important; /* Chrome/Edge/Safari */
width: 0px !important;
height: 0px !important;
}
/* Y-axis custom scrollbar container */
.custom-scrollbar-y {
position: fixed;
top: 0;
right: 0;
width: 8px;
height: 100%;
opacity: 0;
transition: opacity 0.2s ease;
z-index: 9999;
background: rgba(0, 0, 0, 0.05);
}
/* X-axis custom scrollbar container */
.custom-scrollbar-x {
position: fixed;
bottom: 0;
left: 0;
width: 100%;
height: 8px;
opacity: 0;
transition: opacity 0.2s ease;
z-index: 9999;
background: rgba(0, 0, 0, 0.05);
}
/* Custom scrollbar thumb */
.custom-scrollbar-thumb {
position: absolute;
background: #888;
border-radius: 4px;
opacity: 1; /* Always visible */
cursor: pointer;
}
.custom-scrollbar-y .custom-scrollbar-thumb {
width: 100%;
}
.custom-scrollbar-x .custom-scrollbar-thumb {
height: 100%;
}
.custom-scrollbar-thumb:hover {
background: #555;
}
/* Show during scrolling or dragging */
html.scrolling .custom-scrollbar-y,
html.scrolling .custom-scrollbar-x {
opacity: 1;
}
/* Show when hovering over scrollbar */
.custom-scrollbar-y:hover,
.custom-scrollbar-x:hover {
opacity: 1;
}
/* Always show when dragging */
.dragging {
opacity: 1 !important;
}
`;
document.head.appendChild(style);
// Create Y-axis scrollbar
const scrollbarY = document.createElement('div');
scrollbarY.className = 'custom-scrollbar-y';
const thumbY = document.createElement('div');
thumbY.className = 'custom-scrollbar-thumb';
scrollbarY.appendChild(thumbY);
document.body.appendChild(scrollbarY);
// Create X-axis scrollbar
const scrollbarX = document.createElement('div');
scrollbarX.className = 'custom-scrollbar-x';
const thumbX = document.createElement('div');
thumbX.className = 'custom-scrollbar-thumb';
scrollbarX.appendChild(thumbX);
document.body.appendChild(scrollbarX);
// Global variables
let isDraggingY = false;
let isDraggingX = false;
let startY, startX, startScrollTop, startScrollLeft;
let scrollTimeout;
const html = document.documentElement;
function getDocumentDimensions() {
return {
clientWidth: window.innerWidth || html.clientWidth || document.body.clientWidth,
clientHeight: window.innerHeight || html.clientHeight || document.body.clientHeight,
scrollWidth: Math.max(
document.body.scrollWidth, html.scrollWidth,
document.body.offsetWidth, html.offsetWidth,
document.body.clientWidth, html.clientWidth
),
scrollHeight: Math.max(
document.body.scrollHeight, html.scrollHeight,
document.body.offsetHeight, html.offsetHeight,
document.body.clientHeight, html.clientHeight
),
scrollLeft: window.pageXOffset || html.scrollLeft || document.body.scrollLeft,
scrollTop: window.pageYOffset || html.scrollTop || document.body.scrollTop
};
}
function updateScrollbars() {
const dims = getDocumentDimensions();
const maxScrollLeft = dims.scrollWidth - dims.clientWidth;
const maxScrollTop = dims.scrollHeight - dims.clientHeight;
const isScrollableY = dims.scrollHeight > dims.clientHeight;
scrollbarY.style.display = isScrollableY ? 'block' : 'none';
if (isScrollableY) {
const thumbHeightRatio = dims.clientHeight / dims.scrollHeight;
const thumbHeight = Math.max(thumbHeightRatio * dims.clientHeight, 20);
const scrollRatioY = maxScrollTop > 0 ? dims.scrollTop / maxScrollTop : 0;
const thumbTop = scrollRatioY * (dims.clientHeight - thumbHeight);
thumbY.style.height = `${thumbHeight}px`;
thumbY.style.top = `${thumbTop}px`;
}
const isScrollableX = dims.scrollWidth > dims.clientWidth;
scrollbarX.style.display = isScrollableX ? 'block' : 'none';
if (isScrollableX) {
const thumbWidthRatio = dims.clientWidth / dims.scrollWidth;
const thumbWidth = Math.max(thumbWidthRatio * dims.clientWidth, 20);
const scrollRatioX = maxScrollLeft > 0 ? dims.scrollLeft / maxScrollLeft : 0;
const thumbLeft = scrollRatioX * (dims.clientWidth - thumbWidth);
thumbX.style.width = `${thumbWidth}px`;
thumbX.style.left = `${thumbLeft}px`;
}
if (!isDraggingX && !isDraggingY) {
html.classList.add('scrolling');
clearTimeout(scrollTimeout);
scrollTimeout = setTimeout(() => {
html.classList.remove('scrolling');
}, 500);
}
}
thumbY.addEventListener('mousedown', (e) => {
e.preventDefault();
e.stopPropagation();
const dims = getDocumentDimensions();
isDraggingY = true;
startY = e.clientY;
startScrollTop = dims.scrollTop;
scrollbarY.classList.add('dragging');
html.classList.add('scrolling');
document.body.style.userSelect = 'none';
});
thumbX.addEventListener('mousedown', (e) => {
e.preventDefault();
e.stopPropagation();
const dims = getDocumentDimensions();
isDraggingX = true;
startX = e.clientX;
startScrollLeft = dims.scrollLeft;
scrollbarX.classList.add('dragging');
html.classList.add('scrolling');
document.body.style.userSelect = 'none';
});
document.addEventListener('mousemove', (e) => {
if (!isDraggingY && !isDraggingX) return;
const dims = getDocumentDimensions();
if (isDraggingY) {
const deltaY = e.clientY - startY;
const thumbHeight = parseFloat(thumbY.style.height) || 20;
const trackHeight = dims.clientHeight;
const maxScrollTop = dims.scrollHeight - dims.clientHeight;
const scrollRatio = maxScrollTop / (trackHeight - thumbHeight);
const newScrollTop = Math.max(0, Math.min(maxScrollTop, startScrollTop + (deltaY * scrollRatio)));
window.scrollTo(dims.scrollLeft, newScrollTop);
}
if (isDraggingX) {
const deltaX = e.clientX - startX;
const thumbWidth = parseFloat(thumbX.style.width) || 20;
const trackWidth = dims.clientWidth;
const maxScrollLeft = dims.scrollWidth - dims.clientWidth;
const scrollRatio = maxScrollLeft / (trackWidth - thumbWidth);
const newScrollLeft = Math.max(0, Math.min(maxScrollLeft, startScrollLeft + (deltaX * scrollRatio)));
document.documentElement.scrollLeft = newScrollLeft;
document.body.scrollLeft = newScrollLeft;
window.scrollTo(newScrollLeft, dims.scrollTop);
}
updateScrollbars();
});
scrollbarY.addEventListener('mousedown', (e) => {
if (e.target !== scrollbarY) return;
const dims = getDocumentDimensions();
const thumbHeight = parseFloat(thumbY.style.height) || 20;
const clickPos = e.clientY;
const thumbHalf = thumbHeight / 2;
const trackHeight = dims.clientHeight;
const maxScrollTop = dims.scrollHeight - dims.clientHeight;
const clickRatio = (clickPos - thumbHalf) / (trackHeight - thumbHeight);
const newScrollTop = Math.max(0, Math.min(maxScrollTop, clickRatio * maxScrollTop));
window.scrollTo({
top: newScrollTop,
left: dims.scrollLeft,
behavior: 'smooth'
});
});
scrollbarX.addEventListener('mousedown', (e) => {
if (e.target !== scrollbarX) return;
const dims = getDocumentDimensions();
const thumbWidth = parseFloat(thumbX.style.width) || 20;
const clickPos = e.clientX;
const thumbHalf = thumbWidth / 2;
const trackWidth = dims.clientWidth;
const maxScrollLeft = dims.scrollWidth - dims.clientWidth;
const clickRatio = (clickPos - thumbHalf) / (trackWidth - thumbWidth);
const newScrollLeft = Math.max(0, Math.min(maxScrollLeft, clickRatio * maxScrollLeft));
window.scrollTo({
top: dims.scrollTop,
left: newScrollLeft,
behavior: 'smooth'
});
});
function endDragging() {
if (isDraggingY) {
isDraggingY = false;
scrollbarY.classList.remove('dragging');
}
if (isDraggingX) {
isDraggingX = false;
scrollbarX.classList.remove('dragging');
}
document.body.style.userSelect = '';
clearTimeout(scrollTimeout);
scrollTimeout = setTimeout(() => {
html.classList.remove('scrolling');
}, 500);
}
document.addEventListener('mouseup', endDragging);
document.addEventListener('mouseleave', endDragging);
window.addEventListener('scroll', updateScrollbars, { passive: true });
window.addEventListener('resize', updateScrollbars, { passive: true });
function initialize() {
updateScrollbars();
setTimeout(updateScrollbars, 100);
setTimeout(updateScrollbars, 500);
}
if (document.readyState === 'complete') {
initialize();
} else {
window.addEventListener('load', initialize);
}
})();