diff --git a/static/js/speaker.js b/static/js/speaker.js
index 057b109..841ea50 100644
--- a/static/js/speaker.js
+++ b/static/js/speaker.js
@@ -135,17 +135,11 @@ $(function() { sio = (function() {
         canvasPaint.width = canvasPaint.width;
 
         if (id != undefined) {
-
             if (x != undefined && y != undefined) {
-
                 lasers[id] = {x:x, y:y};
-
             } else {
-
                 delete lasers[id];
-
             }
-
         }
 
         for (var laserIndex in lasers) {
@@ -168,8 +162,8 @@ $(function() { sio = (function() {
 
     sio.onMouseDown = function(event) {
 
-        var x = (event.x - canvasPdfBounding.left) / canvasPdf.width;
-        var y = (event.y - canvasPdfBounding.top) / canvasPdf.height;
+        var x = event.offsetX / canvasPdf.width;
+        var y = event.offsetY / canvasPdf.height;
 
         socket.emit('pointer', filename, socket.id, x, y);
 
@@ -184,8 +178,8 @@ $(function() { sio = (function() {
 
         if (pointer) {
 
-            var x = (event.x - canvasPdfBounding.left) / canvasPdf.width;
-            var y = (event.y - canvasPdfBounding.top) / canvasPdf.height;
+            var x = event.offsetX / canvasPdf.width;
+            var y = event.offsetY / canvasPdf.height;
 
             if (shouldUpdatePointer) {
                 // Update
diff --git a/static/js/viewer.js b/static/js/viewer.js
index 63aedbd..d21d068 100644
--- a/static/js/viewer.js
+++ b/static/js/viewer.js
@@ -120,8 +120,8 @@ $(function() { sio = (function() {
 
     sio.onMouseDown = function() {
 
-        var x = (event.x - canvasPdfBounding.left) / canvasPdf.width;
-        var y = (event.y - canvasPdfBounding.top) / canvasPdf.height;
+        var x = event.offsetX / canvasPdf.width;
+        var y = event.offsetY / canvasPdf.height;
 
         socket.emit('pointer', filename, socket.id, x, y);
 
@@ -136,8 +136,8 @@ $(function() { sio = (function() {
 
         if (pointer) {
 
-            var x = (event.x - canvasPdfBounding.left) / canvasPdf.width;
-            var y = (event.y - canvasPdfBounding.top) / canvasPdf.height;
+            var x = event.offsetX / canvasPdf.width;
+            var y = event.offsetY / canvasPdf.height;
 
             if (shouldUpdatePointer) {
                 // Update