diff --git a/README.FRONTEND b/README.FRONTEND
index bb4e6ce..f7cf64c 100644
--- a/README.FRONTEND
+++ b/README.FRONTEND
@@ -36,9 +36,11 @@ serverConnection.onclearchat = ...;
 serverConnection.ondownstream = ...;
 ```
 
-The `onconnected` callback is called when we connect to the server;
-`onclose` is the opposite of `onconnected`.  `onusermessage` indicates
-a message from the server that should be displayed to the user.
+The `onconnected` callback is called when we connect to the server.  The
+`onclose` callback is called when the socket is closed; you should use it
+to close all your outgoing streams (incoming streams will be closed by the
+server).  `onusermessage` indicates a message from the server that should
+be displayed to the user.
 
 The other callbacks will only be called after you join a group.  `onuser`
 is used to indicate that a user has joined or left the current group.
diff --git a/static/sfu.js b/static/sfu.js
index bec86f4..994d063 100644
--- a/static/sfu.js
+++ b/static/sfu.js
@@ -69,6 +69,7 @@ function gotConnected() {
 }
 
 function gotClose(code, reason) {
+    delUpMediaKind(null);
     setConnected(false);
     if(code != 1000)
         console.warn('Socket close', code, reason);
@@ -395,10 +396,15 @@ function delUpMedia(c) {
     setButtonsVisibility()
 }
 
+/**
+ * delUpMediaKind reoves all up media of the given kind.  If kind is
+ * falseish, it removes all up media.
+ * @param {string} kind
+*/
 function delUpMediaKind(kind) {
     for(let id in serverConnection.up) {
         let c = serverConnection.up[id];
-        if(c.kind != kind)
+        if(kind && c.kind != kind)
             continue
         c.close(true);
         delMedia(id);