fix js-service.md (#210)

diff --git a/source/cn/references/js-service.md b/source/cn/references/js-service.md
index 22f95e8..d8be4d4 100644
--- a/source/cn/references/js-service.md
+++ b/source/cn/references/js-service.md
@@ -105,7 +105,7 @@
 ```html
 <script>
 var _InstanceService = new InstanceService(weex)
-var _NormalService = new service.normalService(weex)
+var _NormalService = new service.NormalService(weex)
 
 module.exports = {
   created: fucntion() {
diff --git a/source/references/js-service.md b/source/references/js-service.md
index fffbc09..f93ddae 100644
--- a/source/references/js-service.md
+++ b/source/references/js-service.md
@@ -101,7 +101,7 @@
 ```html
 <script>
 var _InstanceService = new InstanceService(weex)
-var _NormalService = new service.normalService(weex)
+var _NormalService = new service.NormalService(weex)
 
 module.exports = {
   created: function() {