add platform checkcode

Author: bjtqti

modcode/platform.js

@@ -0,0 +1,14 @@
+function isWechat() {
+	var ua = navigator.userAgent.toLowerCase();
+	return /micromessenger/i.test(ua);
+}
+
+function isQQBrowser() {
+	var ua = navigator.userAgent.toLowerCase();
+	return /Mobile MQQBrowser/i.test(ua);
+}
+
+function isAndroid() {
+	var ua = navigator.userAgent.toLowerCase();
+	return /android/i.test(ua);
+}