Improve responsive nav experience

assets/js/_main.js

@@ -1,3 +1,34 @@
+/*! Responsive Menu */
+// http://tympanus.net/codrops/2013/05/08/responsive-retina-ready-menu/
+//  The function to change the class
+var changeClass = function (r,className1,className2) {
+  var regex = new RegExp("(?:^|\\s+)" + className1 + "(?:\\s+|$)");
+  if( regex.test(r.className) ) {
+    r.className = r.className.replace(regex,' '+className2+' ');
+    }
+    else{
+    r.className = r.className.replace(new RegExp("(?:^|\\s+)" + className2 + "(?:\\s+|$)"),' '+className1+' ');
+    }
+    return r.className;
+};  
+//  Creating our button in JS for smaller screens
+var menuElements = document.getElementById('site-nav');
+menuElements.insertAdjacentHTML('afterBegin','<button type="button" role="button" id="menutoggle" class="navtoogle lines-button x" aria-hidden="true"><span class="lines"></span>menu</button>');
+
+//  Toggle the class on click to show / hide the menu
+document.getElementById('menutoggle').onclick = function() {
+  changeClass(this, 'navtoogle active', 'navtoogle');
+};
+// http://tympanus.net/codrops/2013/05/08/responsive-retina-ready-menu/comment-page-2/#comment-438918
+document.onclick = function(e) {
+  var mobileButton = document.getElementById('menutoggle'),
+    buttonStyle =  mobileButton.currentStyle ? mobileButton.currentStyle.display : getComputedStyle(mobileButton, null).display;
+
+  if(buttonStyle === 'block' && e.target !== mobileButton && new RegExp(' ' + 'active' + ' ').test(' ' + mobileButton.className + ' ')) {
+    changeClass(mobileButton, 'navtoogle active', 'navtoogle');
+  }
+};
+
 /*! Plugin options and other jQuery stuff */
 
 // FitVids options