Support reading all filter types from the url

go/blog/blog.go

	var currentFilter = null;
	window.addEventListener("DOMContentLoaded", function(ev) {
		filterFromURL(document.location);
		runFilterFromURL(document.location);
	});
	window.addEventListener("hashchange", function(ev) {
		filterFromURL(new URL(ev.newURL));
		runFilterFromURL(new URL(ev.newURL));
	});
	window.addEventListener("click", function(ev) {
			return;
		}
		var tag = tagFromURL(new URL(ev.target.href));
		if (currentFilter == tag) {
		var filter = filterFromURL(new URL(ev.target.href));
		if (isSameFilter(currentFilter, filter)) {
			clearFilter();
			location.hash = "";
			ev.preventDefault();
		}
	});
	function filterFromURL(u) {
		var tag = tagFromURL(u);
		if (tag == null) {
	function isSameFilter(f1, f2) {
		return f1 && f2 && f1.type == f2.type && f1.argument == f2.argument;
	}
	function runFilterFromURL(u) {
		var filter = filterFromURL(u);
		if (filter == null) {
			clearFilter();
		} else {
			filterTag(tag);
			filter.run(filter.argument);
			currentFilter = filter;
		}
	}
	function tagFromURL(u) {
		if (!u.hash.startsWith("#tag:")) {
	function filterFromURL(u) {
		if (u.hash.startsWith("#tag:")) {
			return { type: "tag", run: filterTag, argument: u.hash.substr(5) };
		} else if (u.hash.startsWith("#title:")) {
			return { type: "title", run: filterTitle, argument: u.hash.substr(7) };
		} else if (u.hash.startsWith("#id:")) {
			return { type: "id", run: filterId, argument: u.hash.substr(4) };
		} else if (u.hash.startsWith("#type:")) {
			return { type: "type", run: filterType, argument: u.hash.substr(6) };
		} else {
			return null;
		}
		return u.hash.substr(5);
	}
	function filterTag(tag) {
		currentFilter = tag;
		var articles = document.querySelectorAll("article");
		for (var i = 0; i < articles.length; i++) {
			var article = articles[i];