--- a/src/chat.js	Sat Nov 09 21:41:11 2024 -0700
+++ b/src/chat.js	Sun Nov 10 19:57:14 2024 -0700
@@ -173,6 +173,7 @@
 }
 
 window.onfocus = function() {
+	// console.log('onfocus');
 	document.title = title;
 	hasUnseen = false;
 };
@@ -207,8 +208,9 @@
 }
 
 setInterval(function(){
+	showOnline();
 	ajax(`heartbeat.js?last_update=${lastUpdate}`);
-}, 60000 );
+}, 10000 );
 
 function resync(updated) {
 	lastUpdate = updated;
@@ -223,3 +225,30 @@
 	sound.play();
 }
 
+let online = {};
+
+function setOnline(userId) {
+	online[userId] = Date.now();
+}
+
+function showOnline() {
+	let old = Date.now() - 20000;
+	for( let id of Object.keys(online) ) {
+		if( online[id] < old )
+			delete online[id];
+	}
+	let a = [];
+	for( let id in online ) {
+		a.push( `span[online="${id}"]` );
+	}
+	let style = document.querySelector('style[online]');
+	if( a.length === 0 ) {
+		style.innerHTML = '';
+	} else {
+		style.innerHTML = `
+			${a.join(', ')} {
+				background-color: green;
+			}
+`		;
+	}
+}