diff --git a/public/index.html b/public/index.html
index a57de338..c1502561 100644
--- a/public/index.html
+++ b/public/index.html
@@ -61,34 +61,34 @@
 	function getBrowerInfo(){
 		var userAgent = window.navigator.userAgent;
 		var browerInfo = {
-			type: '',
-			version: '',
+			type: 'unknown',
+			version: 'unknown',
 			userAgent: userAgent
 		};
 		if(document.documentMode){
 			browerInfo.type = "IE"
 			browerInfo.version = document.documentMode + ''
-		}else if(userAgent.indexOf("Firefox") > -1){
+		}else if(indexOf(userAgent, "Firefox")){
 			browerInfo.type = "Firefox"
 			browerInfo.version = userAgent.match(/Firefox\/([\d.]+)/)[1]
-		}else if(userAgent.indexOf("Opera") > -1){
+		}else if(indexOf(userAgent, "Opera")){
 			browerInfo.type = "Opera"
 			browerInfo.version = userAgent.match(/Opera\/([\d.]+)/)[1]
-		}else if(userAgent.indexOf("Edg") > -1){
+		}else if(indexOf(userAgent, "Edg")){
 			browerInfo.type = "Edg"
 			browerInfo.version = userAgent.match(/Edg\/([\d.]+)/)[1]
-		}else if(userAgent.indexOf("Chrome") > -1){
+		}else if(indexOf(userAgent, "Chrome")){
 			browerInfo.type = "Chrome"
 			browerInfo.version = userAgent.match(/Chrome\/([\d.]+)/)[1]
-		}else if(userAgent.indexOf("Safari") > -1){
+		}else if(indexOf(userAgent, "Safari")){
 			browerInfo.type = "Safari"
 			browerInfo.version = userAgent.match(/Safari\/([\d.]+)/)[1]
-		}else{
-			browerInfo.type = "unknown"
-			browerInfo.version = "unknown"
 		}
 		return browerInfo
 	}
+    function indexOf(userAgent, brower) {
+        return userAgent.indexOf(brower) > -1
+    }
 	function isSatisfyBrower(){
 		var minVer = {
 			"Chrome": 71,
@@ -99,11 +99,7 @@
 		}
 		var browerInfo = getBrowerInfo()
 		var materVer = browerInfo.version.split('.')[0]
-		if(materVer >= minVer[browerInfo.type]){
-			return true
-		}else{
-			return false
-		}
+        return materVer >= minVer[browerInfo.type]
 	}
 	if(!isSatisfyBrower()){
 		document.getElementById('versionCheck').style.display = 'block';