diff --git a/source/Ox.UI/js/Video/Ox.VideoPreview.js b/source/Ox.UI/js/Video/Ox.VideoPreview.js
index e825af5c..59b0b8fa 100644
--- a/source/Ox.UI/js/Video/Ox.VideoPreview.js
+++ b/source/Ox.UI/js/Video/Ox.VideoPreview.js
@@ -35,7 +35,8 @@ Ox.VideoPreview = function(options, self) {
 
     self.$interface = Ox.Element({
             tooltip: function(event) {
-                var position = getPosition(event.offsetX);
+                //event.offsetX does not work in Firefox
+                var position = getPosition(event.clientX - that.offset().left);
                 self.$frame.attr({src: self.options.getFrame(position)});
                 return Ox.formatDuration(position, 2);
             }        
@@ -53,7 +54,8 @@ Ox.VideoPreview = function(options, self) {
 
     function click(e) {
         that.triggerEvent('click', {
-            position: getPosition(e.offsetX)
+            //e.offsetX does not work in Firefox
+            position: getPosition(e.clientX - that.offset().left)
         });
     }
 
@@ -108,4 +110,4 @@ Ox.VideoPreview = function(options, self) {
 
     return that;
 
-};
\ No newline at end of file
+};