diff --git a/assets/www/invert.js b/assets/www/invert.js
new file mode 100644
index 000000000..e29dff1fc
--- /dev/null
+++ b/assets/www/invert.js
@@ -0,0 +1,28 @@
+function load_script(src, callback) {
+    var s = document.createElement('script');
+    s.src = src;
+    s.onload = callback;
+    document.getElementsByTagName('head')[0].appendChild(s);
+}
+
+function invertColors() {
+    var colorProperties = ['color', 'background-color'];
+    $('*').each(function () {
+        var color = null;
+        for (var prop in colorProperties) {
+            prop = colorProperties[prop];
+            if (!$(this).css(prop)) continue;
+            color = new RGBColor($(this).css(prop));
+            if (color.ok) {
+                $(this).css(prop, 'rgb(' + (255 - color.r) + ',' + (255 - color.g) + ',' + (255 - color.b) + ')');
+            }
+            color = null;
+        }
+    });
+}
+
+load_script('file:///android_asset/www/rgb.js', function () {
+    if (!window.jQuery) load_script('file:///android_asset/www/jquery.js', invertColors);
+    else invertColors();
+    alert(2);
+})
diff --git a/assets/www/rgb.js b/assets/www/rgb.js
new file mode 100644
index 000000000..15b0e451b
--- /dev/null
+++ b/assets/www/rgb.js
@@ -0,0 +1,291 @@
+/**
+ * A class to parse color values
+ * @author Stoyan Stefanov <sstoo@gmail.com>
+ * @link   http://www.phpied.com/rgb-color-parser-in-javascript/
+ * @license Use it if you like it
+ */
+
+
+function RGBColor(color_string)
+{
+    this.ok = false;
+
+    // strip any leading #
+    if (color_string.charAt(0) == '#') { // remove # if any
+        color_string = color_string.substr(1,6);
+    }
+
+    color_string = color_string.replace(/ /g,'');
+    color_string = color_string.toLowerCase();
+
+    // before getting into regexps, try simple matches
+    // and overwrite the input
+    var simple_colors = {
+        aliceblue: 'f0f8ff',
+        antiquewhite: 'faebd7',
+        aqua: '00ffff',
+        aquamarine: '7fffd4',
+        azure: 'f0ffff',
+        beige: 'f5f5dc',
+        bisque: 'ffe4c4',
+        black: '000000',
+        blanchedalmond: 'ffebcd',
+        blue: '0000ff',
+        blueviolet: '8a2be2',
+        brown: 'a52a2a',
+        burlywood: 'deb887',
+        cadetblue: '5f9ea0',
+        chartreuse: '7fff00',
+        chocolate: 'd2691e',
+        coral: 'ff7f50',
+        cornflowerblue: '6495ed',
+        cornsilk: 'fff8dc',
+        crimson: 'dc143c',
+        cyan: '00ffff',
+        darkblue: '00008b',
+        darkcyan: '008b8b',
+        darkgoldenrod: 'b8860b',
+        darkgray: 'a9a9a9',
+        darkgreen: '006400',
+        darkkhaki: 'bdb76b',
+        darkmagenta: '8b008b',
+        darkolivegreen: '556b2f',
+        darkorange: 'ff8c00',
+        darkorchid: '9932cc',
+        darkred: '8b0000',
+        darksalmon: 'e9967a',
+        darkseagreen: '8fbc8f',
+        darkslateblue: '483d8b',
+        darkslategray: '2f4f4f',
+        darkturquoise: '00ced1',
+        darkviolet: '9400d3',
+        deeppink: 'ff1493',
+        deepskyblue: '00bfff',
+        dimgray: '696969',
+        dodgerblue: '1e90ff',
+        feldspar: 'd19275',
+        firebrick: 'b22222',
+        floralwhite: 'fffaf0',
+        forestgreen: '228b22',
+        fuchsia: 'ff00ff',
+        gainsboro: 'dcdcdc',
+        ghostwhite: 'f8f8ff',
+        gold: 'ffd700',
+        goldenrod: 'daa520',
+        gray: '808080',
+        green: '008000',
+        greenyellow: 'adff2f',
+        honeydew: 'f0fff0',
+        hotpink: 'ff69b4',
+        indianred : 'cd5c5c',
+        indigo : '4b0082',
+        ivory: 'fffff0',
+        khaki: 'f0e68c',
+        lavender: 'e6e6fa',
+        lavenderblush: 'fff0f5',
+        lawngreen: '7cfc00',
+        lemonchiffon: 'fffacd',
+        lightblue: 'add8e6',
+        lightcoral: 'f08080',
+        lightcyan: 'e0ffff',
+        lightgoldenrodyellow: 'fafad2',
+        lightgrey: 'd3d3d3',
+        lightgreen: '90ee90',
+        lightpink: 'ffb6c1',
+        lightsalmon: 'ffa07a',
+        lightseagreen: '20b2aa',
+        lightskyblue: '87cefa',
+        lightslateblue: '8470ff',
+        lightslategray: '778899',
+        lightsteelblue: 'b0c4de',
+        lightyellow: 'ffffe0',
+        lime: '00ff00',
+        limegreen: '32cd32',
+        linen: 'faf0e6',
+        magenta: 'ff00ff',
+        maroon: '800000',
+        mediumaquamarine: '66cdaa',
+        mediumblue: '0000cd',
+        mediumorchid: 'ba55d3',
+        mediumpurple: '9370d8',
+        mediumseagreen: '3cb371',
+        mediumslateblue: '7b68ee',
+        mediumspringgreen: '00fa9a',
+        mediumturquoise: '48d1cc',
+        mediumvioletred: 'c71585',
+        midnightblue: '191970',
+        mintcream: 'f5fffa',
+        mistyrose: 'ffe4e1',
+        moccasin: 'ffe4b5',
+        navajowhite: 'ffdead',
+        navy: '000080',
+        oldlace: 'fdf5e6',
+        olive: '808000',
+        olivedrab: '6b8e23',
+        orange: 'ffa500',
+        orangered: 'ff4500',
+        orchid: 'da70d6',
+        palegoldenrod: 'eee8aa',
+        palegreen: '98fb98',
+        paleturquoise: 'afeeee',
+        palevioletred: 'd87093',
+        papayawhip: 'ffefd5',
+        peachpuff: 'ffdab9',
+        peru: 'cd853f',
+        pink: 'ffc0cb',
+        plum: 'dda0dd',
+        powderblue: 'b0e0e6',
+        purple: '800080',
+        red: 'ff0000',
+        rosybrown: 'bc8f8f',
+        royalblue: '4169e1',
+        saddlebrown: '8b4513',
+        salmon: 'fa8072',
+        sandybrown: 'f4a460',
+        seagreen: '2e8b57',
+        seashell: 'fff5ee',
+        sienna: 'a0522d',
+        silver: 'c0c0c0',
+        skyblue: '87ceeb',
+        slateblue: '6a5acd',
+        slategray: '708090',
+        snow: 'fffafa',
+        springgreen: '00ff7f',
+        steelblue: '4682b4',
+        tan: 'd2b48c',
+        teal: '008080',
+        thistle: 'd8bfd8',
+        tomato: 'ff6347',
+        turquoise: '40e0d0',
+        violet: 'ee82ee',
+        violetred: 'd02090',
+        wheat: 'f5deb3',
+        white: 'ffffff',
+        whitesmoke: 'f5f5f5',
+        yellow: 'ffff00',
+        yellowgreen: '9acd32'
+    };
+    for (var key in simple_colors) {
+        if (color_string == key) {
+            color_string = simple_colors[key];
+        }
+    }
+    // emd of simple type-in colors
+
+    // array of color definition objects
+    var color_defs = [
+        {
+            re: /^rgb\((\d{1,3}),\s*(\d{1,3}),\s*(\d{1,3})\)$/,
+            example: ['rgb(123, 234, 45)', 'rgb(255,234,245)'],
+            process: function (bits){
+                return [
+                    parseInt(bits[1]),
+                    parseInt(bits[2]),
+                    parseInt(bits[3])
+                ];
+            }
+        },
+        {
+            re: /^(\w{2})(\w{2})(\w{2})$/,
+            example: ['#00ff00', '336699'],
+            process: function (bits){
+                return [
+                    parseInt(bits[1], 16),
+                    parseInt(bits[2], 16),
+                    parseInt(bits[3], 16)
+                ];
+            }
+        },
+        {
+            re: /^(\w{1})(\w{1})(\w{1})$/,
+            example: ['#fb0', 'f0f'],
+            process: function (bits){
+                return [
+                    parseInt(bits[1] + bits[1], 16),
+                    parseInt(bits[2] + bits[2], 16),
+                    parseInt(bits[3] + bits[3], 16)
+                ];
+            }
+        }
+    ];
+
+    // search through the definitions to find a match
+    for (var i = 0; i < color_defs.length; i++) {
+        var re = color_defs[i].re;
+        var processor = color_defs[i].process;
+        var bits = re.exec(color_string);
+        if (bits) {
+            channels = processor(bits);
+            this.r = channels[0];
+            this.g = channels[1];
+            this.b = channels[2];
+            this.ok = true;
+        }
+
+    }
+
+    // validate/cleanup values
+    this.r = (this.r < 0 || isNaN(this.r)) ? 0 : ((this.r > 255) ? 255 : this.r);
+    this.g = (this.g < 0 || isNaN(this.g)) ? 0 : ((this.g > 255) ? 255 : this.g);
+    this.b = (this.b < 0 || isNaN(this.b)) ? 0 : ((this.b > 255) ? 255 : this.b);
+
+    // some getters
+    this.toRGB = function () {
+        return 'rgb(' + this.r + ', ' + this.g + ', ' + this.b + ')';
+    }
+    this.toHex = function () {
+        var r = this.r.toString(16);
+        var g = this.g.toString(16);
+        var b = this.b.toString(16);
+        if (r.length == 1) r = '0' + r;
+        if (g.length == 1) g = '0' + g;
+        if (b.length == 1) b = '0' + b;
+        return '#' + r + g + b;
+    }
+
+    // help
+    this.getHelpXML = function () {
+
+        var examples = new Array();
+        // add regexps
+        for (var i = 0; i < color_defs.length; i++) {
+            var example = color_defs[i].example;
+            for (var j = 0; j < example.length; j++) {
+                examples[examples.length] = example[j];
+            }
+        }
+        // add type-in colors
+        for (var sc in simple_colors) {
+            examples[examples.length] = sc;
+        }
+
+        var xml = document.createElement('ul');
+        xml.setAttribute('id', 'rgbcolor-examples');
+        for (var i = 0; i < examples.length; i++) {
+            try {
+                var list_item = document.createElement('li');
+                var list_color = new RGBColor(examples[i]);
+                var example_div = document.createElement('div');
+                example_div.style.cssText =
+                        'margin: 3px; '
+                        + 'border: 1px solid black; '
+                        + 'background:' + list_color.toHex() + '; '
+                        + 'color:' + list_color.toHex()
+                ;
+                example_div.appendChild(document.createTextNode('test'));
+                var list_item_value = document.createTextNode(
+                    ' ' + examples[i] + ' -> ' + list_color.toRGB() + ' -> ' + list_color.toHex()
+                );
+                list_item.appendChild(example_div);
+                list_item.appendChild(list_item_value);
+                xml.appendChild(list_item);
+
+            } catch(e){}
+        }
+        return xml;
+
+    }
+
+}
+
+
diff --git a/res/menu/main.xml b/res/menu/main.xml
index 8e2bd9450..6e233be3e 100644
--- a/res/menu/main.xml
+++ b/res/menu/main.xml
@@ -61,6 +61,7 @@
         android:orderInCategory="0"
         android:showAsAction="never" />
     
+    <item android:id="@+id/menu_togglenightmode" android:title="@string/menu_togglenightmode" android:orderInCategory="0" android:showAsAction="never"></item>
     <item android:id="@+id/menu_help"
         android:title="@string/menu_help"
 		android:icon="@drawable/action_help"                        
@@ -77,4 +78,5 @@
     
     
     
+    
 </menu>
diff --git a/res/values/strings.xml b/res/values/strings.xml
index 8fd30be6f..e220743a9 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -29,4 +29,5 @@
         <item>Large</item>
     </string-array>
     <string name="menu_exit">Exit</string>
+    <string name="menu_togglenightmode">Toggle night mode</string>
 </resources>
diff --git a/src/org/kiwix/kiwixmobile/KiwixMobileActivity.java b/src/org/kiwix/kiwixmobile/KiwixMobileActivity.java
index f0230b8e1..1ce205a52 100644
--- a/src/org/kiwix/kiwixmobile/KiwixMobileActivity.java
+++ b/src/org/kiwix/kiwixmobile/KiwixMobileActivity.java
@@ -236,6 +236,11 @@ public class KiwixMobileActivity extends Activity {
                 } else if (url.startsWith("file://")) {
                     // To handle help page (loaded from resources)
                     return true;
+                    
+                } else if (url.startsWith("javascript:")){
+                    // Allow javascript for HTML functions and code execution (EX: night mode)
+                    return true;
+                    
                 } else if (url.startsWith(ZimContentProvider.UI_URI.toString())) {
                 	// To handle links which access user interface (i.p. used in help page)
                 	if (url.equals(ZimContentProvider.UI_URI.toString()+"selectzimfile")) {
@@ -421,17 +426,22 @@ public class KiwixMobileActivity extends Activity {
 
 			    selectZimFile();
 			    break;
-			    
+
+            case R.id.menu_exit:
+            	finish();
+            	break;
+            
             case R.id.menu_settings:
             	// Display the fragment as the main content.
             	Intent i = new Intent(this, KiwixSettings.class);
                 startActivityForResult(i, PREFERENCES_REQUEST_CODE);
             	break;
-
-            case R.id.menu_exit:
-            	finish();
-            	break;
+            	
+            case R.id.menu_togglenightmode:
+            	ToggleNightMode();
+            	break;         
         }
+        
         return super.onOptionsItemSelected(item);
     }
 
@@ -631,6 +641,11 @@ public class KiwixMobileActivity extends Activity {
 		imm.hideSoftInputFromWindow(articleSearchtextView.getWindowToken(),0);
 	}
 	
+	private void ToggleNightMode(){
+		String JSInvert = "javascript:function load_script(src,callback){var s=document.createElement('script');s.src=src;s.onload=callback;document.getElementsByTagName('head')[0].appendChild(s);}load_script('file:///android_asset/www/invert.js');";
+		webView.loadUrl(JSInvert);
+	}
+	
 	private void setDefaultZoom() {
 		DisplayMetrics metrics = new DisplayMetrics();
 		getWindowManager().getDefaultDisplay().getMetrics(metrics);