Update js.md

XinHuaLuFang · XinHuaLuFang · commit 2de8623a89d1 · 2015-08-13T15:32:40.000+08:00
diff --git a/js.md b/js.md
@@ -148,6 +148,12 @@ $(function () {
 
 ```
 
+- 某年某月的1号为星期几
+```
+	var weekday = ["星期日", "星期一", "星期二", "星期三", "星期四", "星期五", "星期六"];
+	weekday[new Date(2015, 9, 1).getDay()];	//2015年10月1号
+```
+
 #### 2. Mobile - js
 
 
@@ -193,4 +199,4 @@ WeixinJSBridge.invoke('getBrandWCPayRequest', d, function(res){
     }
     loading.hide();
 });
-```
+```
