diff --git a/www/js/qrcode.js b/www/js/qrcode.js
index 1b5a036..79ae312 100644
--- a/www/js/qrcode.js
+++ b/www/js/qrcode.js
@@ -1,16 +1,27 @@
+var brightness;
+var bvalue;
+var setted= false;
 var app = {
 
     // Application Constructor
     initialize: function() {
         document.addEventListener('deviceready', this.onDeviceReady.bind(this), false);
     },
-
     onDeviceReady: function() {
         var uid = window.localStorage.getItem("token");
-        this.loadQrcode();
+        app.loadQrcode();
         setInterval(function () {
             window.location.reload();
         },100000);
+
+        brightness = cordova.plugins.brightness;
+        if(brightness){
+          brightness.getBrightness(function(val){
+              bvalue = val;
+          }, function(err){
+            console.log(err);
+          });
+        }
     },
     loadQrcode: function() {
         $.showLoading("加载中");
@@ -27,6 +38,38 @@
                       colorLight: "#ffffff",
                       correctLevel: QRCode.CorrectLevel.L
                     });
+                    if(!setted&&brightness){
+                      brightness.setBrightness(1, function(ret){
+                        console.log(ret);
+                        setted = true;
+                        brightness.setKeepScreenOn(true);
+                      }, function(e){
+                        console.log(e)
+                      });
+                    }
+                } else {
+                    $.hideLoading();
+                    $.alert("请求失败，请稍后再试", "错误");
+                }
+            } else {
+                $.hideLoading();
+                $.alert("请求失败了:" + ret.status + "请稍后再试", "错误");
+            }
+        })
+    },
+    refresh:function(){
+      V1Qrcode(function(ok, ret) {
+            if (ok) {
+                if (ret.code == 200) {
+                    $.hideLoading();
+                    var qrcode = new QRCode(document.getElementById("qrcode"), {
+                      text: ret.qrcode,
+                      width: 200,
+                      height: 200,
+                      colorDark: "#000000",
+                      colorLight: "#ffffff",
+                      correctLevel: QRCode.CorrectLevel.L
+                    });
                 } else {
                     $.hideLoading();
                     $.alert("请求失败，请稍后再试", "错误");
@@ -37,28 +80,15 @@
             }
         })
     },
-    refresh:function(){
-      V1Qrcode(function(ok, ret) {
-            if (ok) {
-                if (ret.code == 200) {
-                    $.hideLoading();
-                    var qrcode = new QRCode(document.getElementById("qrcode"), {
-                      text: ret.qrcode,
-                      width: 150,
-                      height: 150,
-                      colorDark: "#000000",
-                      colorLight: "#ffffff",
-                      correctLevel: QRCode.CorrectLevel.L
-                    });
-                } else {
-                    $.hideLoading();
-                    $.alert("请求失败，请稍后再试", "错误");
-                }
-            } else {
-                $.hideLoading();
-                $.alert("请求失败了:" + ret.status + "请稍后再试", "错误");
-            }
-        })
+    backTo:function(){
+      if(brightness&&bvalue){
+        brightness.setBrightness(bvalue, function(ret){
+          brightness.setKeepScreenOn(false);
+        }, function(e){
+          console.log(e)
+        });
+      } 
+      window,location.href='main.html';
     }
 };
 app.initialize();
\ No newline at end of file