diff --git a/lib/ace/lib/dom.js b/lib/ace/lib/dom.js
index 34549916..74a71123 100644
--- a/lib/ace/lib/dom.js
+++ b/lib/ace/lib/dom.js
@@ -39,72 +39,86 @@ exports.createElement = function(tag, ns) {
            document.createElement(tag);
 };
 
-exports.setText = function(elem, text) {
-    if (elem.innerText !== undefined) {
-        elem.innerText = text;
-    }
-    if (elem.textContent !== undefined) {
-        elem.textContent = text;
-    }
-};
+if (typeof DOMTokenList === 'function') {
+    exports.hasCssClass = function(el, name) {
+        return el.classList.contains(name);
+    };
 
-exports.hasCssClass = function(el, name) {
-    var classes = el.className.split(/\s+/g);
-    return classes.indexOf(name) !== -1;
-};
+    exports.addCssClass = function(el, name) {
+        el.classList.add(name);
+    };
 
-/*
-* Add a CSS class to the list of classes on the given node
-*/
-exports.addCssClass = function(el, name) {
-    if (!exports.hasCssClass(el, name)) {
-        el.className += " " + name;
+    exports.removeCssClass = function(el, name) {
+        el.classList.remove(name);
     }
-};
 
-/*
-* Remove a CSS class from the list of classes on the given node
-*/
-exports.removeCssClass = function(el, name) {
-    var classes = el.className.split(/\s+/g);
-    while (true) {
-        var index = classes.indexOf(name);
-        if (index == -1) {
-            break;
+    exports.toggleCssClass = function(el, name) {
+        el.classList.toggle(name);
+    }
+
+    exports.setCssClass = function(el, name, include) {
+        el.classList[include ? 'add' : 'remove'](name);
+    }
+}
+else {
+    exports.hasCssClass = function(el, name) {
+        var classes = el.className.split(/\s+/g);
+        return classes.indexOf(name) !== -1;
+    };
+
+    /*
+    * Add a CSS class to the list of classes on the given node
+    */
+    exports.addCssClass = function(el, name) {
+        if (!exports.hasCssClass(el, name)) {
+            el.className += " " + name;
         }
-        classes.splice(index, 1);
-    }
-    el.className = classes.join(" ");
-};
+    };
 
-exports.toggleCssClass = function(el, name) {
-    var classes = el.className.split(/\s+/g), add = true;
-    while (true) {
-        var index = classes.indexOf(name);
-        if (index == -1) {
-            break;
+    /*
+    * Remove a CSS class from the list of classes on the given node
+    */
+    exports.removeCssClass = function(el, name) {
+        var classes = el.className.split(/\s+/g);
+        while (true) {
+            var index = classes.indexOf(name);
+            if (index == -1) {
+                break;
+            }
+            classes.splice(index, 1);
         }
-        add = false;
-        classes.splice(index, 1);
-    }
-    if(add)
-        classes.push(name);
+        el.className = classes.join(" ");
+    };
 
-    el.className = classes.join(" ");
-    return add;
-};
+    exports.toggleCssClass = function(el, name) {
+        var classes = el.className.split(/\s+/g), add = true;
+        while (true) {
+            var index = classes.indexOf(name);
+            if (index == -1) {
+                break;
+            }
+            add = false;
+            classes.splice(index, 1);
+        }
+        if(add)
+            classes.push(name);
 
-/*
- * Add or remove a CSS class from the list of classes on the given node
- * depending on the value of <tt>include</tt>
- */
-exports.setCssClass = function(node, className, include) {
-    if (include) {
-        exports.addCssClass(node, className);
-    } else {
-        exports.removeCssClass(node, className);
-    }
-};
+        el.className = classes.join(" ");
+        return add;
+    };
+
+    /*
+     * Add or remove a CSS class from the list of classes on the given node
+     * depending on the value of <tt>include</tt>
+     */
+    exports.setCssClass = function(node, className, include) {
+        if (include) {
+            exports.addCssClass(node, className);
+        } else {
+            exports.removeCssClass(node, className);
+        }
+    };
+}
 
 exports.hasCssString = function(id, doc) {
     var index = 0, sheets;
@@ -143,7 +157,7 @@ exports.importCssString = function importCssString(cssText, id, doc) {
         if (id)
             style.id = id;
 
-        var head = doc.getElementsByTagName("head")[0] || doc.documentElement;
+        var head = doc.head || doc.getElementsByTagName("head")[0] || doc.documentElement;
         head.appendChild(style);
     }
 };
@@ -156,7 +170,7 @@ exports.importCssStylsheet = function(uri, doc) {
         link.rel = 'stylesheet';
         link.href = uri;
 
-        var head = doc.getElementsByTagName("head")[0] || doc.documentElement;
+        var head = doc.head || doc.getElementsByTagName("head")[0] || doc.documentElement;
         head.appendChild(link);
     }
 };
@@ -273,7 +287,7 @@ exports.getInnerText = function(el) {
     if (document.body && "textContent" in document.body)
         return el.textContent;
     else
-         return el.innerText || el.textContent || "";
+         return el.innerText;
 };
 
 exports.getParentWindow = function(document) {