Fix hover/click bug, obj might be null

git-svn-id: https://flot.googlecode.com/svn/trunk@287 1e0a6537-2640-0410-bfb7-f154510ff394

examples/pie.html

@@ -269,12 +269,16 @@ $(function () {
 
 function pieHover(event, pos, obj) 
 {
+	if (!obj)
+                return;
 	percent = parseFloat(obj.series.percent).toFixed(2);
 	$("#hover").html('<span style="font-weight: bold; color: '+obj.series.color+'">'+obj.series.label+' ('+percent+'%)</span>');
 }
 
 function pieClick(event, pos, obj) 
 {
+	if (!obj)
+                return;
 	percent = parseFloat(obj.series.percent).toFixed(2);
 	alert(''+obj.series.label+': '+percent+'%');
 }