--- a/mobile/android/chrome/content/browser.js
+++ b/mobile/android/chrome/content/browser.js
@@ -3937,38 +3937,38 @@ var BrowserEventHandler = {
         // the user wanted, and neither can any non-root sub-frame, cancel the
         // override so that Java can handle panning the main document.
         let data = JSON.parse(aData);
 
         // round the scroll amounts because they come in as floats and might be
         // subject to minor rounding errors because of zoom values. I've seen values
         // like 0.99 come in here and get truncated to 0; this avoids that problem.
         let zoom = BrowserApp.selectedTab._zoom;
-        data.x = Math.round(data.x / zoom);
-        data.y = Math.round(data.y / zoom);
+        let x = Math.round(data.x / zoom);
+        let y = Math.round(data.y / zoom);
 
         if (this._firstScrollEvent) {
           while (this._scrollableElement != null &&
-                 !this._elementCanScroll(this._scrollableElement, data.x, data.y))
+                 !this._elementCanScroll(this._scrollableElement, x, y))
             this._scrollableElement = this._findScrollableElement(this._scrollableElement, false);
 
           let doc = BrowserApp.selectedBrowser.contentDocument;
           if (this._scrollableElement == null ||
               this._scrollableElement == doc.body ||
               this._scrollableElement == doc.documentElement) {
             sendMessageToJava({ gecko: { type: "Panning:CancelOverride" } });
             return;
           }
 
           this._firstScrollEvent = false;
         }
 
         // Scroll the scrollable element
-        if (this._elementCanScroll(this._scrollableElement, data.x, data.y)) {
-          this._scrollElementBy(this._scrollableElement, data.x, data.y);
+        if (this._elementCanScroll(this._scrollableElement, x, y)) {
+          this._scrollElementBy(this._scrollableElement, x, y);
           sendMessageToJava({ gecko: { type: "Gesture:ScrollAck", scrolled: true } });
           SelectionHandler.subdocumentScrolled(this._scrollableElement);
         } else {
           sendMessageToJava({ gecko: { type: "Gesture:ScrollAck", scrolled: false } });
         }
 
         break;
       }
@@ -3977,24 +3977,25 @@ var BrowserEventHandler = {
         this._cancelTapHighlight();
         break;
 
       case "Gesture:SingleTap": {
         let element = this._highlightElement;
         if (element) {
           try {
             let data = JSON.parse(aData);
+            let [x, y] = [data.x, data.y];
             if (ElementTouchHelper.isElementClickable(element)) {
-              [data.x, data.y] = this._moveClickPoint(element, data.x, data.y);
-              element = ElementTouchHelper.anyElementFromPoint(data.x, data.y);
+              [x, y] = this._moveClickPoint(element, x, y);
+              element = ElementTouchHelper.anyElementFromPoint(x, y);
             }
 
-            this._sendMouseEvent("mousemove", element, data.x, data.y);
-            this._sendMouseEvent("mousedown", element, data.x, data.y);
-            this._sendMouseEvent("mouseup",   element, data.x, data.y);
+            this._sendMouseEvent("mousemove", element, x, y);
+            this._sendMouseEvent("mousedown", element, x, y);
+            this._sendMouseEvent("mouseup",   element, x, y);
 
             // See if its a input element
             if ((element instanceof HTMLInputElement && element.mozIsTextField(false)) ||
                 (element instanceof HTMLTextAreaElement))
                SelectionHandler.showThumb(element);
           } catch(e) {
             Cu.reportError(e);
           }