diff --git a/src/js/actions/LevelActions.js b/src/js/actions/LevelActions.js
index 80638ccd..5aebff8f 100644
--- a/src/js/actions/LevelActions.js
+++ b/src/js/actions/LevelActions.js
@@ -18,7 +18,14 @@ var LevelActions = {
     AppDispatcher.handleViewAction({
       type: ActionTypes.RESET_LEVELS_SOLVED
     });
-  }
+  },
+
+  setIsSolvingLevel: function(isSolvingLevel) {
+    AppDispatcher.handleViewAction({
+      type: ActionTypes.SET_IS_SOLVING_LEVEL,
+      isSolvingLevel: isSolvingLevel,
+    });
+  },
 
 };
 
diff --git a/src/js/app/index.js b/src/js/app/index.js
index 98568d1c..fce24fbe 100644
--- a/src/js/app/index.js
+++ b/src/js/app/index.js
@@ -75,6 +75,10 @@ var init = function() {
   window.LocaleStore = LocaleStore;
   window.LocaleActions = LocaleActions;
   window.intl = intl;
+
+  $(window).on('beforeunload', function(e) {
+    return GlobalStateStore.getIsSolvingLevel() ? 'you have a level in progress' : null;
+  });
 };
 
 var vcsModeRefresh = function(eventData) {
diff --git a/src/js/constants/AppConstants.js b/src/js/constants/AppConstants.js
index 1c8c80bd..26a32bcd 100644
--- a/src/js/constants/AppConstants.js
+++ b/src/js/constants/AppConstants.js
@@ -32,7 +32,8 @@ module.exports = {
      * solve the level, not ask for solution
      * or solve it again.
      */
-    SOLVE_LEVEL: null
+    SOLVE_LEVEL: null,
+    SET_IS_SOLVING_LEVEL: null,
   }),
 
   PayloadSources: keyMirror({
diff --git a/src/js/level/index.js b/src/js/level/index.js
index 4e66f433..4dff1703 100644
--- a/src/js/level/index.js
+++ b/src/js/level/index.js
@@ -58,6 +58,7 @@ var Level = Sandbox.extend({
     this.startOffCommand();
 
     this.handleOpen(options.deferred);
+    LevelActions.setIsSolvingLevel(true);
   },
 
   getIsGoalExpanded: function() {
@@ -65,6 +66,7 @@ var Level = Sandbox.extend({
   },
 
   handleOpen: function(deferred) {
+    LevelActions.setIsSolvingLevel(true);
     deferred = deferred || Q.defer();
 
     // if there is a multiview in the beginning, open that
@@ -573,6 +575,7 @@ var Level = Sandbox.extend({
     delete this.mainVis;
     delete this.goalVis;
     delete this.goalCanvasHolder;
+    LevelActions.setIsSolvingLevel(false);
   },
 
   getInstantCommands: function() {
diff --git a/src/js/stores/GlobalStateStore.js b/src/js/stores/GlobalStateStore.js
index 74f4e47f..732ea203 100644
--- a/src/js/stores/GlobalStateStore.js
+++ b/src/js/stores/GlobalStateStore.js
@@ -10,6 +10,7 @@ var _isAnimating = false;
 var _flipTreeY = false;
 var _numLevelsSolved = 0;
 var _disableLevelInstructions = false;
+var _isSolvingLevel = false;
 
 var GlobalStateStore = Object.assign(
 {},
@@ -20,6 +21,10 @@ AppConstants.StoreSubscribePrototype,
     return _isAnimating;
   },
 
+  getIsSolvingLevel: function() {
+    return _isSolvingLevel;
+  },
+
   getFlipTreeY: function() {
     return _flipTreeY;
   },
@@ -37,6 +42,10 @@ AppConstants.StoreSubscribePrototype,
     var shouldInform = false;
 
     switch (action.type) {
+      case ActionTypes.SET_IS_SOLVING_LEVEL:
+        _isSolvingLevel = action.isSolvingLevel;
+        shouldInform = true;
+        break;
       case ActionTypes.CHANGE_IS_ANIMATING:
         _isAnimating = action.isAnimating;
         shouldInform = true;