check if cb is a function

diff --git a/js/foundation.util.timerAndImageLoader.js b/js/foundation.util.timerAndImageLoader.js
index b5facd02f3d3095b07916d7ec894fced478c6990..2e9f9e6738161d7601702979385f87a593fd2709 100644 (file)
--- a/js/foundation.util.timerAndImageLoader.js
+++ b/js/foundation.util.timerAndImageLoader.js
@@ -29,7 +29,7 @@ function Timer(elem, options, cb) {
       if(options.infinite){
         _this.restart();//rerun the timer.
       }
-      cb();
+      if (cb && typeof cb === 'function') { cb(); }
     }, remain);
     elem.trigger(`timerstart.zf.${nameSpace}`);
   }