Fixes #445: Avoid overlapping replots

libraries/jquery/vtchart.js

@@ -13,6 +13,7 @@
         this.element = false;
         
         this.init = function(element,data,options) {
+           jQuery(element).empty(); /* Clear any existing content to avoid overlapping redraw */
            vtChart.prototype.init.call(this,element,data,options);
         }
         
@@ -32,10 +33,10 @@
             console.log('supported interface not found!');
            
         return this.each(function(index,element){
-            var jQElement = jQuery(element);
+            var jQElement = jQuery(element).empty(); /* Clear any existing content to avoid overlapping redraw */
             var instance = new vtChart();
             instance.init(jQElement,data[0],data[1]);
         });
     }
     
-})( jQuery );
\ No newline at end of file
+})( jQuery );