diff --git a/tracker/index.js b/tracker/index.js
index fc8458b0..8f58fae3 100644
--- a/tracker/index.js
+++ b/tracker/index.js
@@ -134,19 +134,25 @@ import { removeTrailingSlash } from '../lib/url';
 
   const handlePush = (state, title, url) => {
     removeEvents();
+    // url is not guaranteed
+    // thus calling `url.toString()` might causes exception, then break the pjax update
+    // track only if url is validate
+    if (url) {
+      currentRef = currentUrl;
+      const newUrl = url.toString();
 
-    currentRef = currentUrl;
-    const newUrl = url.toString();
-
-    if (newUrl.substring(0, 4) === 'http') {
-      currentUrl = '/' + newUrl.split('/').splice(3).join('/');
-    } else {
-      currentUrl = newUrl;
+      if (newUrl.substring(0, 4) === 'http') {
+        currentUrl = '/' + newUrl.split('/').splice(3).join('/');
+      } else {
+        currentUrl = newUrl;
+      }
+      // this function under some framework might be called multiple times
+      // thus only track if currentUrl and currentRef are not same
+      if (currentUrl !== currentRef) {
+        trackView(currentUrl, currentRef);
+        setTimeout(addEvents, 300);
+      }
     }
-
-    trackView(currentUrl, currentRef);
-
-    setTimeout(addEvents, 300);
   };
 
   /* Global */