diff --git a/engine.io.js b/engine.io.js
index 6c0b575e2..76f74851d 100644
--- a/engine.io.js
+++ b/engine.io.js
@@ -1345,7 +1345,8 @@ return /******/ (function(modules) { // webpackBootstrap
 	  if (typeof attachEvent === 'function') {
 	    attachEvent('onunload', unloadHandler);
 	  } else if (typeof addEventListener === 'function') {
-	    addEventListener('beforeunload', unloadHandler, false);
+	    var terminationEvent = 'onpagehide' in self ? 'pagehide' : 'unload';
+	    addEventListener(terminationEvent, unloadHandler, false);
 	  }
 	}
 
@@ -4039,7 +4040,7 @@ return /******/ (function(modules) { // webpackBootstrap
 /* 25 */
 /***/ function(module, exports, __webpack_require__) {
 
-	'use strict';
+	/* WEBPACK VAR INJECTION */(function(global) {'use strict';
 
 	/**
 	 * Module requirements.
@@ -4073,6 +4074,13 @@ return /******/ (function(modules) { // webpackBootstrap
 
 	function empty() {}
 
+	/**
+	 * Until https://github.com/tc39/proposal-global is shipped.
+	 */
+	function glob() {
+	  return typeof self !== 'undefined' ? self : typeof window !== 'undefined' ? window : typeof global !== 'undefined' ? global : {};
+	}
+
 	/**
 	 * JSONP Polling constructor.
 	 *
@@ -4089,8 +4097,8 @@ return /******/ (function(modules) { // webpackBootstrap
 	  // we do this here (lazily) to avoid unneeded global pollution
 	  if (!callbacks) {
 	    // we need to consider multiple engines in the same page
-	    if (!window.___eio) window.___eio = [];
-	    callbacks = window.___eio;
+	    var global = glob();
+	    callbacks = global.___eio = global.___eio || [];
 	  }
 
 	  // callback identifier
@@ -4271,6 +4279,7 @@ return /******/ (function(modules) { // webpackBootstrap
 	    this.iframe.onload = complete;
 	  }
 	};
+	/* WEBPACK VAR INJECTION */}.call(exports, (function() { return this; }())))
 
 /***/ },
 /* 26 */
diff --git a/package.json b/package.json
index cf6b0b3de..004b1130d 100644
--- a/package.json
+++ b/package.json
@@ -2,7 +2,7 @@
   "name": "engine.io-client",
   "description": "Client for the realtime Engine",
   "license": "MIT",
-  "version": "3.3.0",
+  "version": "3.3.1",
   "main": "lib/index.js",
   "homepage": "https://github.com/socketio/engine.io-client",
   "contributors": [
@@ -45,7 +45,7 @@
     "concat-stream": "^1.6.0",
     "del": "^2.2.2",
     "derequire": "^2.0.6",
-    "engine.io": "3.3.0",
+    "engine.io": "3.3.1",
     "eslint-config-standard": "4.4.0",
     "eslint-plugin-standard": "1.3.1",
     "expect.js": "^0.3.1",