minor fix

web/desktop.system

@@ -4433,6 +4433,8 @@
         });
 
         function getCoordinateFromEvent(e){
+            var x = -1;
+            var y = -1;
             if (e.originalEvent == undefined){
                 e.originalEvent = e;
             }
@@ -4443,6 +4445,9 @@
             } else if (e.type == 'mousedown' || e.type == 'mouseup' || e.type == 'mousemove' || e.type == 'mouseover'|| e.type=='mouseout' || e.type=='mouseenter' || e.type=='mouseleave') {
                 x = e.clientX;
                 y = e.clientY;
+            }else{
+                x = e.clientX;
+                y = e.clientY;
             }
             return [x,y];
         }