only show last few debug messages

server/djrandom/frontend/static/css/style.css

@@ -216,3 +216,8 @@ table.summary {
    font-size: 75%;
    color: #999;
 }
+
+#debug p {
+   margin: 0;
+   padding: 0;
+}

server/djrandom/frontend/static/js/djr/player.js

@@ -459,7 +459,11 @@ djr.player = function() {
 
 // Debugging.
 djr.debug = function(msg) {
-  $('#debug').append(msg + '<br>');
+  var n_logs = $('#debug p').length;
+  if (n_logs > 7) {
+    $('#debug p:first').remove();
+  }
+  $('#debug').append('<p>' + msg + '</p>');
 };
 
 // An error has occurred in the player.