* refactor codes.

src/js/device.js

@@ -16,43 +16,34 @@
 
     var resetCssClass = function() {
         var width = $window.width();
-        var classNames = '';
-
-        if (width >= desktopLg) {
-            classNames += ' screen-desktop-wide';
-        } else if (width >= desktop && width < desktopLg) {
-            classNames += ' screen-desktop';
-        } else if (width >= tablet && width < desktop) {
-            classNames += ' screen-tablet';
-        } else {
-            classNames += ' screen-phone';
-        }
-        if (width < desktop) {
-            classNames += ' device-mobile';
-        } else {
-            classNames += ' device-desktop';
-        }
-        if ('ontouchstart' in document.documentElement) {
-            classNames += ' is-touchable';
-        }
-
-        var userAgent = navigator.userAgent;
-        if (userAgent.match(/(iPad|iPhone|iPod)/i)) {
-            classNames += ' os-ios';
-        } else if (userAgent.match(/android/i)) {
-            classNames += ' os-android';
-        } else if (userAgent.match(/Win/i)) {
-            classNames += ' os-windows';
-        } else if (userAgent.match(/Mac/i)) {
-            classNames += ' os-mac';
-        } else if (userAgent.match(/Linux/i)) {
-            classNames += ' os-linux';
-        } else if (userAgent.match(/X11/i)) {
-            classNames += ' os-unix';
-        }
-        $('html').addClass(classNames);
+        $('html').toggleClass('screen-desktop', width >= desktop && width < desktopLg)
+            .toggleClass('screen-desktop-wide', width >= desktopLg)
+            .toggleClass('screen-tablet', width >= tablet && width < desktop)
+            .toggleClass('screen-phone', width < tablet)
+            .toggleClass('device-mobile', width < desktop)
+            .toggleClass('device-desktop', width >= desktop);
     };
 
+    var classNames = '';
+    var userAgent = navigator.userAgent;
+    if (userAgent.match(/(iPad|iPhone|iPod)/i)) {
+        classNames += ' os-ios';
+    } else if (userAgent.match(/android/i)) {
+        classNames += ' os-android';
+    } else if (userAgent.match(/Win/i)) {
+        classNames += ' os-windows';
+    } else if (userAgent.match(/Mac/i)) {
+        classNames += ' os-mac';
+    } else if (userAgent.match(/Linux/i)) {
+        classNames += ' os-linux';
+    } else if (userAgent.match(/X11/i)) {
+        classNames += ' os-unix';
+    }
+    if ('ontouchstart' in document.documentElement) {
+        classNames += ' is-touchable';
+    }
+    $('html').addClass(classNames);
+
     $window.resize(resetCssClass);
     resetCssClass();
 }(window, jQuery));