Much better

static/main.js

@@ -0,0 +1,60 @@
+function request(url, callback) {
+    let xhr = new XMLHttpRequest();
+    xhr.onreadystatechange = () => {
+        if (xhr.readyState === XMLHttpRequest.DONE) {
+            if (xhr.status === 200) {
+                callback(xhr.responseText);
+            }
+        }
+    };
+
+    xhr.open('GET', url, true);
+    xhr.send(null);
+}
+
+function refreshElement(element, url) {
+    request(url, (response) => { element.innerHTML = response });
+}
+
+function isRunning(callback) {
+    request('is-running', (response) => {
+        callback(response === 'yes');
+    });
+}
+
+function refresh() {
+    refreshElement(document.getElementById('leaderboard'), 'leaderboard');
+    refreshElement(document.getElementById('battles'), 'battles');
+}
+
+
+function watch() {
+    isRunning((running) => {
+        if (running) {
+            setTimeout(watch, 1000);
+        } else {
+            isCurrentlyRunning = false;
+            refresh();
+            runningElement.style.display = "None";
+        }
+    });
+}
+
+function updateDots() {
+    dotsElement.innerHTML += ".";
+    if (dotsElement.innerHTML === "....") {
+        dotsElement.innerHTML = ".";
+    }
+    if (isCurrentlyRunning) {
+        setTimeout(updateDots, 500);
+    }
+}
+
+let runningElement = document.getElementById('running');
+let dotsElement = document.getElementById('dots');
+let isCurrentlyRunning = runningElement.style.display === '';
+
+if (isCurrentlyRunning) {
+    watch();
+    updateDots();
+}