diff --git a/docs/markdown/contribution.zh-CN.md b/docs/markdown/contribution.zh-CN.md
index 326336137..6ec67e4c9 100644
--- a/docs/markdown/contribution.zh-CN.md
+++ b/docs/markdown/contribution.zh-CN.md
@@ -15,6 +15,32 @@
 - 当新增组件或者修改原有组件时，记得增加或者修改测试代码，保证代码的稳定
 - 在 PR 中请添加合适的描述，并关联相关的 Issue
 
+### Pull Request 流程
+
+1. fork 主仓库，如果已经 fork 过，请同步主仓库的最新代码
+2. 基于 fork 后仓库的 dev 分支新建一个分支，比如`feature/button_color`
+3. 在新分支上进行开发，开发完成后，提 Pull Request 到主仓库的 dev 分支
+4. Pull Request 会在 Review 通过后被合并到主仓库
+5. 等待 Vant 发布版本，一般是每周一次
+
+### 同步教程
+
+提 Pull Request 前，请依照下面的流程同步主仓库的最新代码
+
+```bash
+# 添加主仓库到 remote，作为 fork 后仓库的上游仓库
+git remote add upstream https://github.com/youzan/vant.git
+
+# 拉取主仓库最新代码
+git fetch upstream
+
+# 切换至 dev 分支
+git checkout dev
+
+# 合并主仓库代码
+git merge upstream/dev
+```
+
 ### 初始化项目
 
 ```bash
diff --git a/package.json b/package.json
index eb56ba36a..a068abae9 100644
--- a/package.json
+++ b/package.json
@@ -57,7 +57,8 @@
     "@babel/runtime": "^7.4.4",
     "@vant/icons": "1.1.7",
     "@vue/babel-helper-vue-jsx-merge-props": "^1.0.0-beta.3",
-    "vue-lazyload": "1.2.3"
+    "vue-lazyload": "1.2.3",
+    "webpack-dev-server": "^3.3.1"
   },
   "peerDependencies": {
     "vue": ">= 2.5.0"
diff --git a/packages/checkbox/index.js b/packages/checkbox/index.js
index 8eaad0f1d..0589fc450 100644
--- a/packages/checkbox/index.js
+++ b/packages/checkbox/index.js
@@ -30,7 +30,15 @@ export default sfc({
 
   methods: {
     toggle() {
-      this.checked = !this.checked;
+      const checked = !this.checked;
+
+      // When toggle method is called multiple times at the same time,
+      // only the last call is valid.
+      // This is a hack for usage inside Cell.
+      clearTimeout(this.toggleTask);
+      this.toggleTask = setTimeout(() => {
+        this.checked = checked;
+      });
     },
 
     onClickIcon() {
diff --git a/packages/checkbox/test/index.spec.js b/packages/checkbox/test/index.spec.js
index 5c2572b60..5920d5899 100644
--- a/packages/checkbox/test/index.spec.js
+++ b/packages/checkbox/test/index.spec.js
@@ -1,8 +1,8 @@
 import Checkbox from '..';
 import CheckboxGroup from '../../checkbox-group';
-import { mount } from '../../../test/utils';
+import { mount, later } from '../../../test/utils';
 
-test('switch checkbox', () => {
+test('switch checkbox', async () => {
   const wrapper = mount(Checkbox);
 
   wrapper.vm.$on('input', value => {
@@ -11,8 +11,9 @@ test('switch checkbox', () => {
 
   const icon = wrapper.find('.van-checkbox__icon');
   icon.trigger('click');
+  await later();
   icon.trigger('click');
-
+  await later();
   expect(wrapper.emitted('input')).toEqual([[true], [false]]);
   expect(wrapper.emitted('change')).toEqual([[true], [false]]);
 });
@@ -42,7 +43,7 @@ test('label disabled', () => {
   expect(wrapper.emitted('input')).toBeFalsy();
 });
 
-test('checkbox group', () => {
+test('checkbox group', async () => {
   const wrapper = mount({
     template: `
       <checkbox-group v-model="result" :max="2">
@@ -63,11 +64,15 @@ test('checkbox group', () => {
 
   const icons = wrapper.findAll('.van-checkbox__icon');
   icons.at(0).trigger('click');
+  await later();
   icons.at(1).trigger('click');
+  await later();
   icons.at(2).trigger('click');
   expect(wrapper.vm.result).toEqual(['a', 'b']);
 
+  await later();
   icons.at(0).trigger('click');
+  await later();
   expect(wrapper.vm.result).toEqual(['b']);
 });
 
diff --git a/packages/mixins/checkbox.js b/packages/mixins/checkbox.js
index a9412c67f..38eb353fd 100644
--- a/packages/mixins/checkbox.js
+++ b/packages/mixins/checkbox.js
@@ -56,7 +56,6 @@ export const CheckboxMixin = (parent, bem) => ({
       <div
         class={bem()}
         onClick={event => {
-          event.stopPropagation();
           this.$emit('click', event);
         }}
       >
diff --git a/packages/pull-refresh/index.js b/packages/pull-refresh/index.js
index 90d07ca89..9baab8cbd 100644
--- a/packages/pull-refresh/index.js
+++ b/packages/pull-refresh/index.js
@@ -144,7 +144,7 @@ export default sfc({
     const text = this[`${status}Text`] || t(status);
     const style = {
       transition: `${this.duration}ms`,
-      transform: `translate3d(0,${this.height}px, 0)`
+      transform: this.height ? `translate3d(0,${this.height}px, 0)` : ''
     };
 
     const Status = this.slots(status) || [
diff --git a/packages/pull-refresh/test/__snapshots__/demo.spec.js.snap b/packages/pull-refresh/test/__snapshots__/demo.spec.js.snap
index d2b343f62..b83f947f5 100644
--- a/packages/pull-refresh/test/__snapshots__/demo.spec.js.snap
+++ b/packages/pull-refresh/test/__snapshots__/demo.spec.js.snap
@@ -3,7 +3,7 @@
 exports[`renders demo correctly 1`] = `
 <div>
   <div class="van-pull-refresh">
-    <div class="van-pull-refresh__track" style="transition:0ms;transform:translate3d(0,0px, 0);">
+    <div class="van-pull-refresh__track" style="transition:0ms;transform:;">
       <div class="van-pull-refresh__head"></div>
       <div>
         <p>刷新次数: 0</p>
diff --git a/packages/pull-refresh/test/__snapshots__/index.spec.js.snap b/packages/pull-refresh/test/__snapshots__/index.spec.js.snap
index 42f860fa5..c2a9e28c5 100644
--- a/packages/pull-refresh/test/__snapshots__/index.spec.js.snap
+++ b/packages/pull-refresh/test/__snapshots__/index.spec.js.snap
@@ -46,7 +46,7 @@ exports[`change head content when pulling down 4`] = `
 
 exports[`change head content when pulling down 5`] = `
 <div class="van-pull-refresh">
-  <div class="van-pull-refresh__track" style="transition: 300ms; transform: translate3d(0,0px, 0);">
+  <div class="van-pull-refresh__track" style="transition: 300ms;">
     <div class="van-pull-refresh__head"></div>
   </div>
 </div>
@@ -54,7 +54,7 @@ exports[`change head content when pulling down 5`] = `
 
 exports[`not in page top 1`] = `
 <div class="van-pull-refresh">
-  <div class="van-pull-refresh__track" style="transition: 0ms; transform: translate3d(0,0px, 0);">
+  <div class="van-pull-refresh__track" style="transition: 0ms;">
     <div class="van-pull-refresh__head"></div>
   </div>
 </div>
diff --git a/yarn.lock b/yarn.lock
index 1de631553..e6b689b02 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -5218,7 +5218,7 @@ jest-changed-files@^24.8.0:
     execa "^1.0.0"
     throat "^4.0.0"
 
-jest-cli@^24.8.0:
+jest-cli@^24.7.1:
   version "24.8.0"
   resolved "https://registry.yarnpkg.com/jest-cli/-/jest-cli-24.8.0.tgz#b075ac914492ed114fa338ade7362a301693e989"
   integrity sha512-+p6J00jSMPQ116ZLlHJJvdf8wbjNbZdeSX9ptfHX06/MSNaXmKihQzx5vQcw0q2G6JsdVkUIdWbOWtSnaYs3yA==