diff --git a/docs/config.rst b/docs/config.rst
index 042ae0d..ac3e35f 100644
--- a/docs/config.rst
+++ b/docs/config.rst
@@ -216,6 +216,8 @@ the form ``key = value``. Two items take a different form:, ``worlds`` and
 
     **You must specify at least one render**
 
+.. _outputdir:
+
 ``outputdir = "<output directory path>"``
     This is the path to the output directory where the rendered tiles will
     be saved.
@@ -250,11 +252,38 @@ the form ``key = value``. Two items take a different form:, ``worlds`` and
     observer to be used. The observer object is expected to have at least ``start``,
     ``add``, ``update``, and ``finish`` methods.
 
-    e.g.::
+    If you want to specify an observer manually, try something like:
+    ::
 
+        from observer import ProgressBarObserver()
         observer = ProgressBarObserver()
 
-.. _outputdir:
+    There are currently three observers available: ``LoggingObserver``, 
+    ``ProgressBarObserver`` and ``JSObserver``. 
+
+    ``LoggingObserver``
+         This gives the normal/older style output and is the default when output
+         is redirected to a file or when running on Windows
+
+    ``ProgressBarObserver``
+        This is used by default when the output is a terminal. Displays a text based
+        progress bar and some statistics.
+
+    ``JSObserver``
+        This will display render progress on the output map in the bottom right
+        corner of the screen. ``JSObserver`` must be invoked with two parameters.
+
+        The first is output directory. For simplicity, specify this as ``outputdir``
+        and place this line after setting ``outputdir = "<output directory path>"``.
+        
+        The second parameter is the  minimum interval between progress updates in 
+        seconds. Progress information won't be written to file or requested by 
+        your web browser more frequently than this interval. 
+        ::
+
+                from observer import JSObserver
+                observer = JSObserver(outputdir, 10)
+
 
 
 .. _renderdict:
diff --git a/overviewer_core/data/js_src/util.js b/overviewer_core/data/js_src/util.js
index 0e738da..3d6c36e 100644
--- a/overviewer_core/data/js_src/util.js
+++ b/overviewer_core/data/js_src/util.js
@@ -58,6 +58,10 @@ overviewer.util = {
         var coordsdiv = new overviewer.views.CoordboxView({tagName: 'DIV'});
         coordsdiv.render();
 
+        var progressdiv = new overviewer.views.ProgressView({tagName: 'DIV'});
+        progressdiv.render();
+        progressdiv.updateProgress();
+
         if (overviewer.collections.haveSigns) {
             var signs = new overviewer.views.SignControlView();
             signs.registerEvents(signs);
diff --git a/overviewer_core/data/js_src/views.js b/overviewer_core/data/js_src/views.js
index 323c1fc..e66267e 100644
--- a/overviewer_core/data/js_src/views.js
+++ b/overviewer_core/data/js_src/views.js
@@ -108,7 +108,27 @@ overviewer.views.CoordboxView = Backbone.View.extend({
     }
 });
 
-
+overviewer.views.ProgressView = Backbone.View.extend({	
+    initialize: function() {
+        this.el.id = 'progressDiv';
+        this.el.innerHTML = 'Current Render Progress';
+        overviewer.map.controls[google.maps.ControlPosition.BOTTOM_RIGHT].push(this.el);
+        this.hidden = true;
+        $.ajaxSetup({cache: false});
+    },
+    updateProgress: function() {
+        e = this;
+        $.getJSON('progress.js', null, function(d){
+            e.el.hidden = false;
+            e.el.innerHTML = d['message'];
+            if (d.update > 0) {
+                setTimeout("e.updateProgress()", d.update);
+            } else {
+                e.el.hidden = true;
+            }
+        });
+    }
+});
 
 /* GoogleMapView is responsible for dealing with the GoogleMaps API to create the 
  */
diff --git a/overviewer_core/data/web_assets/overviewer.css b/overviewer_core/data/web_assets/overviewer.css
index 0ae76e5..e1f1527 100644
--- a/overviewer_core/data/web_assets/overviewer.css
+++ b/overviewer_core/data/web_assets/overviewer.css
@@ -86,7 +86,7 @@ body {
 }
 
 
-#link, #coordsDiv {
+#link, #coordsDiv, #progressDiv {
     background-color: #fff; /* fallback */
     background-color: rgba(255,255,255,0.55);
     border: 1px solid rgb(0, 0, 0);
diff --git a/overviewer_core/observer.py b/overviewer_core/observer.py
index c58a0d9..7db5061 100644
--- a/overviewer_core/observer.py
+++ b/overviewer_core/observer.py
@@ -17,6 +17,7 @@ import time
 import logging
 import progressbar
 import sys
+import os
 
 class Observer(object):
     """Base class that defines the observer interface.
@@ -164,3 +165,96 @@ class ProgressBarObserver(progressbar.ProgressBar, Observer):
 
     def _need_update(self):
         return self.get_current_value() - self.last_update > self.UPDATE_INTERVAL
+
+class JSObserver(Observer):
+    """Display progress on index.html using JavaScript
+    """
+
+    def __init__(self, outputdir, minrefresh=5):
+        """Initialise observer
+        outputdir must be set to the map output directory path
+        minrefresh specifies the minimum gap between requests, in seconds
+        """
+        self.last_update = -11
+        self.last_update_time = -1 
+        self._current_value = -1
+        self.minrefresh = 1000*minrefresh
+        self.logfile = open(os.path.join(outputdir, "progress.js"), "w+", 0)
+
+    def start(self, max_value):
+        self.logfile.seek(0)
+        self.logfile.write('{"message": "Rendering %d tiles", "update": %s}' % (max_value, self.minrefresh))
+        self.logfile.truncate()
+        self.logfile.flush()
+        self.start_time=time.time()
+        self._set_max_value(max_value)
+
+    def is_started(self):
+        return self.start_time is not None
+
+    def finish(self):
+        """Signals the end of the processes, should be called after the
+        process is done.
+        """
+        self.end_time = time.time()
+        duration = self.end_time - self.start_time
+        self.logfile.seek(0)
+        self.logfile.write('{"message": "Render completed in %dm %ds", "update": "false"}' % (duration//60, duration - duration//60))
+        self.logfile.truncate()
+        self.logfile.close()
+
+    def is_finished(self):
+        return self.end_time is not None
+
+    def is_running(self):
+        return self.is_started() and not self.is_finished()
+
+    def add(self, amount):
+        """Shortcut to update by increments instead of absolute values. Zero
+        amounts are ignored.
+        """
+        if amount:
+            self.update(self.get_current_value() + amount)
+
+    def update(self, current_value):
+        """Set the progress value. Should be between 0 and max_value. Returns
+        whether this update is actually displayed.
+        """
+        self._current_value = current_value
+        if self._need_update():
+            refresh = max(1500*(time.time() - self.last_update_time), self.minrefresh)
+            self.logfile.seek(0)
+            self.logfile.write('{"message": "Rendered %d of %d tiles (%d%%)", "update": %d }' % (self.get_current_value(), self.get_max_value(), self.get_percentage(), refresh))
+            self.logfile.truncate()
+            self.logfile.flush()
+            self.last_update_time = time.time()
+            self.last_update = current_value
+            return True
+        return False
+
+    def get_percentage(self):
+        """Get the current progress percentage. Assumes 100% if max_value is 0
+        """
+        if self.get_max_value() is 0:
+            return 100.0
+        else:
+            return self.get_current_value() * 100.0 / self.get_max_value()
+
+    def get_current_value(self):
+        return self._current_value
+
+    def get_max_value(self):
+        return self._max_value
+
+    def _set_max_value(self, max_value):
+        self._max_value = max_value 
+
+    def _need_update(self):
+        cur_val = self.get_current_value()
+        if cur_val < 100:
+            return cur_val - self.last_update > 10
+        elif cur_val < 500:
+            return cur_val - self.last_update > 50
+        else:
+            return cur_val - self.last_update > 100
+
diff --git a/overviewer_core/settingsDefinition.py b/overviewer_core/settingsDefinition.py
index d2e357c..cfb6539 100644
--- a/overviewer_core/settingsDefinition.py
+++ b/overviewer_core/settingsDefinition.py
@@ -45,7 +45,7 @@
 
 from settingsValidators import *
 import util
-from observer import ProgressBarObserver, LoggingObserver
+from observer import ProgressBarObserver, LoggingObserver, JSObserver
 import platform
 import sys