diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,3 +1,7 @@
+## 3.0.2.2
+
+* Improvements to ping's javascript script. [#494](https://github.com/yesodweb/wai/pull/494)
+
 ## 3.0.2.1
 
 * Relax upper bound on process
diff --git a/Network/Wai/Handler/Launch.hs b/Network/Wai/Handler/Launch.hs
--- a/Network/Wai/Handler/Launch.hs
+++ b/Network/Wai/Handler/Launch.hs
@@ -84,7 +84,7 @@
     Z.finishInflate inflate >>= sendInner . fromByteString
 
 toInsert :: S.ByteString
-toInsert = "<script>setInterval(function(){var x;if(window.XMLHttpRequest){x=new XMLHttpRequest();}else{x=new ActiveXObject(\"Microsoft.XMLHTTP\");}x.open(\"GET\",\"/_ping\",false);x.send();},60000)</script>"
+toInsert = "<script>setInterval(function(){var x;if(window.XMLHttpRequest){x=new XMLHttpRequest();}else{x=new ActiveXObject(\"Microsoft.XMLHTTP\");}x.open(\"GET\",\"/_ping?\" + (new Date()).getTime(),true);x.send();},60000)</script>"
 
 addInsideHead :: (Builder -> IO ())
               -> IO ()
diff --git a/wai-handler-launch.cabal b/wai-handler-launch.cabal
--- a/wai-handler-launch.cabal
+++ b/wai-handler-launch.cabal
@@ -1,5 +1,5 @@
 Name:                wai-handler-launch
-Version:             3.0.2.1
+Version:             3.0.2.2
 Synopsis:            Launch a web app in the default browser.
 description:         API docs and the README are available at <http://www.stackage.org/package/wai-handler-launch>.
 License:             MIT