diff --git a/ace/index.html b/ace/index.html
index 2a9f858..c68d729 100644
--- a/ace/index.html
+++ b/ace/index.html
@@ -50,8 +50,8 @@
         <div class="toolbar">
             <!--<button id="btnSave" onClick="save()" class="btn btn_g">save</button>-->
             <button id="btnUndo" onClick="editor.undo()" class="btn">↶</button>
-            <button id="btnRedo" onClick="editor.redo()" class="btn_g">↷</button>
-          	<button id="btnFs" onclick="openFullscreen();">◻</button>
+            <button id="btnRedo" onClick="editor.redo()" class="btn btn_g">↷</button>
+          	<button id="btnFs" onclick="openFullscreen() class="btn"">◻</button>
         </div>
         <div class="inner" id="editor"></div>
         
@@ -99,20 +99,33 @@
                 }
             });
 
-          function openFullscreen() {
-            var elem = document.documentElement;
-            if (elem.requestFullscreen) {
-              elem.requestFullscreen();
-            } else if (elem.mozRequestFullScreen) { /* Firefox */
-              elem.mozRequestFullScreen();
-            } else if (elem.webkitRequestFullscreen) { /* Chrome, Safari and Opera */
-              elem.webkitRequestFullscreen();
-            } else if (elem.msRequestFullscreen) { /* IE/Edge */
-              elem.msRequestFullscreen();
+            function fullscreen() {
+                if (window.fullScreen) {
+                    var elem = document.documentElement;
+                    if (elem.requestFullscreen) {
+                        elem.requestFullscreen();
+                    } else if (elem.mozRequestFullScreen) { /* Firefox */
+                        elem.mozRequestFullScreen();
+                    } else if (elem.webkitRequestFullscreen) { /* Chrome, Safari and Opera */
+                        elem.webkitRequestFullscreen();
+                    } else if (elem.msRequestFullscreen) { /* IE/Edge */
+                        elem.msRequestFullscreen();
+                    }
+                }
+                else {
+                    if (document.exitFullscreen) {
+                        document.exitFullscreen();
+                    } else if (document.mozCancelFullScreen) {
+                        document.mozCancelFullScreen();
+                    } else if (document.webkitExitFullscreen) {
+                        document.webkitExitFullscreen();
+                    } else if (document.msExitFullscreen) {
+                        document.msExitFullscreen();
+                    }
+                }
             }
-          }
           
-          window.editor = editor;
+            window.editor = editor;
           
         </script>