+function undisplay(element) {
+ element.style.display="none";
+}
+
+function add_message(severity, message) {
+ message = `<div class="message ${severity}" onclick="undisplay(this)">
+<span class="hide-button" onclick="undisplay(this.parentElement)">×</span>
+${message}
+</div>`;
+ const message_area = document.getElementById('message-area');
+ message_area.insertAdjacentHTML('beforeend', message);
+}
+
+const events = new EventSource("events");
+
+events.onerror = function(event) {
+ if (event.target.readyState === EventSource.CLOSED) {
+ add_message("danger", "Connection to server lost.");
+ }
+};
+
+events.addEventListener("move", event => {
+ const square = JSON.parse(event.data);
+
+ window.game.receiveMove(square);
+});
+