diff --git a/js/worker-util.js b/js/worker-util.js
index 4e226a27..77a2a6b6 100644
--- a/js/worker-util.js
+++ b/js/worker-util.js
@@ -6,7 +6,7 @@ const workerUtil = (() => {
   const loadedScripts = new Set();
   return {createWorker, createAPI, loadScript, cloneError};
 
-  function createWorker({url, lifeTime = 30}) {
+  function createWorker({url, lifeTime = 300}) {
     let worker;
     let id;
     let timer;