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43 lines
1.2 KiB
JavaScript
43 lines
1.2 KiB
JavaScript
(function() {
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var pending = false, prevVal = null;
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function updateSoon() {
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if (!pending) {
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pending = true;
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setTimeout(update, 250);
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}
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}
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function update() {
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pending = false;
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var marks = document.getElementById("nav").getElementsByTagName("a"), found;
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for (var i = 0; i < marks.length; ++i) {
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var mark = marks[i], m;
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if (mark.getAttribute("data-default")) {
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if (found == null) found = i;
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} else if (m = mark.href.match(/#(.*)/)) {
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var ref = document.getElementById(m[1]);
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if (ref && ref.getBoundingClientRect().top < 50)
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found = i;
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}
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}
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if (found != null && found != prevVal) {
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prevVal = found;
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var lis = document.getElementById("nav").getElementsByTagName("li");
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for (var i = 0; i < lis.length; ++i) lis[i].className = "";
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for (var i = 0; i < marks.length; ++i) {
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if (found == i) {
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marks[i].className = "active";
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for (var n = marks[i]; n; n = n.parentNode)
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if (n.nodeName == "LI") n.className = "active";
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} else {
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marks[i].className = "";
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}
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}
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}
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}
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window.addEventListener("scroll", updateSoon);
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window.addEventListener("load", updateSoon);
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})();
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