Takazudo · June 20, 2014 08:57 · Jun 20, 2014
diff --git a/head.js b/head.js
@@ -0,0 +1,61 @@
+/**
+ * `html` class tweaking
+ */
+(function() {
+
+  var html = document.getElementsByTagName("html")[0];
+
+  /* helpers */
+
+  var hasClass = function(node, cls) {
+    return new RegExp("(\\s|^)" + cls + "(\\s|$)").test(node.className);
+  };
+
+  var addClass = function(node, cls) {
+    if (hasClass(node, cls)) {
+      return;
+    }
+    return node.className = "" + node.className + " " + cls;
+  };
+
+  var removeClass = function(node, cls) {
+    if (!hasClass(node, cls)) {
+      return;
+    }
+    node.className = node.className
+      .replace(new RegExp("(\\s|^)" + cls + "(\\s|$)"), " ")
+      .replace(/\s+/g, " ").replace(/^\s|\s$/, "");
+  };
+
+  /* UA detection */
+
+  var ua = (function(){
+    var ua = {};
+    var navigator = window.navigator;
+    var platforms = [
+      { property: 'platform', regex: /iPhone/i, identity: 'iPhone' },
+      { property: 'platform', regex: /iPod/i, identity: 'iPod' },
+      { property: 'userAgent', regex: /iPad/i, identity: 'iPad' },
+      { property: 'userAgent', regex: /Blackberry/i, identity: 'Blackberry' },
+      { property: 'userAgent', regex: /Android/i, identity: 'Android' },
+      { property: 'platform', regex: /Mac/i, identity: 'Mac' },
+      { property: 'platform', regex: /Win/i, identity: 'Windows' },
+      { property: 'platform', regex: /Linux/i, identity: 'Linux' }
+    ];
+    for(var i=0, l=platforms.length, platform; i<l; i++){
+      platform = platforms[i];
+      ua[platform.identity] = platform.regex.test(navigator[platform.property]);
+    }
+    return ua;
+  })();
+
+  /* do it */
+
+  if(ua.Windows) {
+    addClass(html, 'os-win');
+  }
+  if(ua.Mac) {
+    addClass(html, 'os-mac');
+  }
+
+}());