diff --git a/cmd/mtwebmapper/web/js/auto-update.js b/cmd/mtwebmapper/web/js/auto-update.js
new file mode 100644
index 0000000..6ee763a
--- /dev/null
+++ b/cmd/mtwebmapper/web/js/auto-update.js
@@ -0,0 +1,132 @@
+L.Control.AutoUpdate = L.Control.extend({
+    options: {
+        position: 'topleft',
+        label: 'Automatic update'
+    },
+
+    onAdd: function() {
+        var container = L.DomUtil.create('div', 'leaflet-bar leaflet-control');
+        container.innerHTML = '<form><input id="autoUpdateCb" type="checkbox"/>'
+            + this.options.label + '</form>';
+        L.DomEvent.on(container, 'click', this.cbClick, this);
+        return container;
+    },
+
+    cbClick: function (e) {
+        L.DomEvent.stopPropagation(e);
+        this.intendedFunction(e);
+        if (e.target.checked) {
+            this.autoUpdate();
+        }
+        if (!e.target.checked) {
+            this.stopUpdate();
+        }
+    },
+
+    intendedFunction: function() {
+        alert('no function selected');
+    },
+
+    stopUpdate: function() {
+        this.socket.close();
+    },
+
+    autoUpdate: function() {
+        this.socket = new WebSocket('ws://' + window.location.host + '/ws');
+
+        this.socket.onmessage = function(evt) {
+
+            var invalidate = function(json) {
+                var invalidateAll = function(x, y, z) { return true };
+
+                if (!(typeof json === "string")) {
+                    return invalidateAll;
+                }
+                var tiles;
+                try {
+                    tiles = JSON.parse(json);
+                } catch (err) {
+                    return invalidateAll;
+                }
+
+                var pyramid = new Array(9);
+                var last = new Object();
+                pyramid[8] = last;
+
+                for (var i = 0; i < tiles.length; i++) {
+                    var xz = tiles[i];
+                    last[xz.X + "#" + xz.Z] = xz;
+                }
+                for (var p = 7; p >= 0; p--) {
+                    var prev = pyramid[p+1]
+                    var curr = new Object();
+                    pyramid[p] = curr;
+                    for (var k in prev) {
+                        if (prev.hasOwnProperty(k)) {
+                            var oxz = prev[k]
+                            var nxz = { X: oxz.X >> 1, Z: oxz.Z >> 1 };
+                            curr[nxz.X + "#" + nxz.Z] = nxz;
+                        }
+                    }
+                }
+                return function(x, y, z) {
+                    if (y > 8) {
+                        x >>= y - 8;
+                        z >>= y - 8;
+                        y = 8;
+                    }
+                    var level = pyramid[y];
+                    var k = x + "#" + z;
+                    return level.hasOwnProperty(k);
+                };
+            } (evt.data);
+
+            var tiles = document.getElementsByTagName('img');
+            var re = /\/map\/([0-9]+)\/([0-9]+)\/([0-9]+).*/;
+            for (var i = 0; i < tiles.length; i++) {
+                var img = tiles[i];
+                var cl = img.getAttribute('class');
+                if (!cl.contains('leaflet-tile-loaded')) {
+                    continue;
+                }
+                var src = img.src;
+                var coord = src.match(re);
+                if (coord == null) {
+                    continue;
+                }
+                var y = parseInt(coord[1], 10);
+                var x = parseInt(coord[2], 10);
+                var z = parseInt(coord[3], 10);
+                if (invalidate(x, y, z)) {
+                    var idx = src.lastIndexOf('#');
+                    if (idx >= 0) {
+                        src = src.substring(0, idx);
+                    }
+                    img.src = src + '#' + Math.random();
+                }
+            }
+        };
+    }
+});
+
+L.autoUpdate = function(cbLabel, cbFunc, cbMap) {
+    var control = new L.Control.AutoUpdate();
+    if (cbLabel) {
+        control.options.label = cbLabel;
+    }
+
+    if (cbFunc) {
+        control.intendedFunction = cbFunc;
+    }
+
+    if (cbMap === '') {
+        return control;
+    }
+    else if (cbMap) {
+        cbMap.addControl(control);
+    }
+    else {
+        map.addControl(control);
+    }
+    return control;
+};