diff --git a/example/ding-dong-bot.js b/example/ding-dong-bot.js
index 47614af8a75144a5fd4080c3653a1d3ccc3f1e99..c1a266b141dd2c972fdf18583fd72c1f3f51f3b9 100644
--- a/example/ding-dong-bot.js
+++ b/example/ding-dong-bot.js
@@ -28,7 +28,7 @@ Please wait... I'm trying to login in...
 `
 
 console.log(welcome)
-const bot = new Wechaty({head: true})
+const bot = new Wechaty({head: 'chrome'})
 
 bot
 .on('login'	,   user => log.info('Bot', 'logined'))
diff --git a/src/puppet-web-browser.js b/src/puppet-web-browser.js
index 658b316cd4697dddf3e3bfb33b0fd4b2628d4570..f320c5d711618f3b7fa4381234e29ae0616dd55e 100644
--- a/src/puppet-web-browser.js
+++ b/src/puppet-web-browser.js
@@ -16,8 +16,13 @@ const retryPromise  = require('retry-promise').default // https://github.com/ola
 
 class Browser {
   constructor(options) {
+    log.verbose('Browser', 'constructor()')
     options   = options       || {}
-    this.head = options.head  || false // default to headless
+    if (typeof options.head === 'undefined') {
+      this.head = false // default
+    } else {
+      this.head = options.head
+    }
   }
 
   toString() { return `Class Browser({head:${this.head})` }
@@ -25,23 +30,42 @@ class Browser {
   init() {
     return this.initDriver()
     .then(() => this)
-    .catch(e => {   // XXX: must has a `.catch` here, or promise will hang! 2016/6/7
-      log.error('Browser', 'init() rejectec: %s', e)
-      throw e
-    })
+    // XXX: if no `.catch` here, promise will hang!
+    // XXX: https://github.com/SeleniumHQ/selenium/issues/2233
+    .catch(e => throw e)
+
+    // console.log(p)
+    // return p.catch()
+    // .catch(e => {   // XXX: must has a `.catch` here, or promise will hang! 2016/6/7
+    //   log.error('Browser', 'init() rejectec: %s', e)
+    //   throw e
+    // })
   }
 
   initDriver() {
-    log.verbose('Browser', 'init()')
+    log.verbose('Browser', 'initDriver(head: %s)', this.head)
     if (this.head) {
-      this.driver = new WebDriver.Builder()
-      .setAlertBehavior('ignore')
-      .forBrowser('chrome')
-      .build()
+      if (/firefox/i.test(this.head)) {
+        this.driver = new WebDriver.Builder()
+        .setAlertBehavior('ignore')
+        .forBrowser('firefox')
+        .build()
+      } else { // default to chrome
+        this.driver = new WebDriver.Builder()
+        .setAlertBehavior('ignore')
+        .forBrowser('chrome')
+        .build()
+      }
     } else {
       this.driver = this.getPhantomJsDriver()
     }
-    return Promise.resolve(this.driver)
+    // console.log(this.driver)
+    return new Promise((resolve, reject) => {
+      // XXX: if no `setTimeout()` here, promise will hang!
+      // XXX: https://github.com/SeleniumHQ/selenium/issues/2233
+      setTimeout(() => { resolve(this.driver) }, 0)
+      // resolve(this.driver)
+    })
   }
 
   open() {
diff --git a/test/webdriver-spec.js b/test/webdriver-spec.js
index 80907f895f3ec9ff30ec11a5f43aef063f3ec7fc..6228e39107c0b9fbfae2b9c7dbc15433955c463a 100644
--- a/test/webdriver-spec.js
+++ b/test/webdriver-spec.js
@@ -5,7 +5,7 @@ const co    = require('co')
 const test   = require('tap').test
 const log   = require('npmlog')
 // log.level = 'verbose'
-// log.level = 'silly'
+log.level = 'silly'
 
 const WebDriver = require('selenium-webdriver')
 const Browser = WebDriver.Browser
@@ -14,6 +14,7 @@ const By = WebDriver.By
 const PuppetWebBrowser  = require('../src/puppet-web-browser')
 const PuppetWebBridge   = require('../src/puppet-web-bridge')
 const PORT = 58788
+const HEAD = 'chrome' // undefined
 
 function driverProcessNum() {
   return new Promise((resolve, reject) => {
@@ -28,12 +29,13 @@ function driverProcessNum() {
 
 test('WebDriver process create & quit test', function(t) {
   co(function* () {
-    const b = new PuppetWebBrowser({port: PORT})
+    const b = new PuppetWebBrowser({port: PORT, head: HEAD})
     t.ok(b, 'Browser instnace')
 
     yield b.init()
+    t.pass('inited')
     yield b.open()
-    t.pass('inited & opened')
+    t.pass('opened')
 
     let n = yield driverProcessNum()
     t.ok(n > 0, 'driver process exist')