Highlights active section in sidebar TOC on SEP articles
// ==UserScript==
// @name SEP TOC Scroll Spy
// @namespace http://tampermonkey.net/
// @version 3.1
// @description Highlights active section in sidebar TOC on SEP articles
// @author You
// @match https://plato.stanford.edu/entries/*
// @icon https://www.google.com/s2/favicons?sz=64&domain=stanford.edu
// @grant none
// @inject-into content
// @noframes
// @license MIT
// @run-at document-end
// ==/UserScript==
var script = document.createElement('script');
script.textContent = '(' + function() {
window.addEventListener("load", function() {
setTimeout(function() {
var toc = document.getElementById("toc");
if (!toc) return;
var tocLinks = toc.querySelectorAll('a[href^="#"]');
var sections = [];
for (var i = 0; i < tocLinks.length; i++) {
var id = tocLinks[i].getAttribute("href").slice(1);
var t = document.getElementById(id);
if (t) sections.push({ target: t, link: tocLinks[i] });
}
if (!sections.length) return;
var style = document.createElement("style");
style.textContent = "#toc a.toc-active{color:#7ba4ff !important;font-weight:600 !important;border-left:2px solid #7ba4ff;padding-left:6px;margin-left:-8px;}";
document.head.appendChild(style);
var hw = document.getElementById("header-wrapper");
var ticking = false;
function isMobile() {
return window.innerWidth <= 768 || (window.innerWidth <= 1024 && !window.matchMedia('(hover: hover)').matches);
}
function update() {
if (isMobile()) { ticking = false; return; }
var scrollY = window.pageYOffset;
if (hw) {
var desiredTop = Math.max(10, hw.getBoundingClientRect().bottom + 10);
toc.style.setProperty("top", desiredTop + "px", "important");
toc.style.setProperty("max-height", "calc(100vh - " + (desiredTop + 20) + "px)", "important");
}
var checkY = scrollY + 200;
var current = null;
for (var j = sections.length - 1; j >= 0; j--) {
var r = sections[j].target.getBoundingClientRect();
if (r.top + scrollY <= checkY) { current = sections[j]; break; }
}
if (!current && sections.length) current = sections[0];
for (var k = 0; k < tocLinks.length; k++) tocLinks[k].classList.remove("toc-active");
if (current) {
current.link.classList.add("toc-active");
var tr = toc.getBoundingClientRect();
var lr = current.link.getBoundingClientRect();
if (lr.top < tr.top + 10 || lr.bottom > tr.bottom - 10)
current.link.scrollIntoView({ block: "nearest", behavior: "smooth" });
}
ticking = false;
}
window.addEventListener("scroll", function() {
if (!ticking) { requestAnimationFrame(update); ticking = true; }
});
// Run immediately and a few more times to catch layout shifts
update();
setTimeout(update, 100);
setTimeout(update, 500);
setTimeout(update, 1000);
}, 1500);
});
} + ')()';
document.documentElement.appendChild(script);