Update foo

static/views/session/script.js

@@ -0,0 +1,9 @@
+var text = document.getElementById("msg").innerText
+msg = JSON.parse(text)
+
+document.getElementById("btn-leave-session").onclick = async (e) => await fetch('api/leave_session', {
+                    method: 'POST', body: JSON.stringify({})
+                });
+var session = msg.session;
+document.getElementById("session").innerText = session["name"];
+document.getElementById('label-username').innerText = msg.username;

static/views/session/template.html

@@ -0,0 +1,3 @@
+Welcome to <b id="session"></b>, <span id="label-username"></span>
+<br><br>
+<button id="btn-leave-session">Leave Session</button>