diff --git a/demo/startup.js b/demo/startup.js
index 5778e6a0..1403fd1b 100644
--- a/demo/startup.js
+++ b/demo/startup.js
@@ -59,48 +59,42 @@ exports.launch = function(env) {
     var emacs = require("ace/keyboard/keybinding/emacs").Emacs;
     var HashHandler = require("ace/keyboard/hash_handler").HashHandler;
     
-    var WorkerClient = require("ace/worker/worker_client").WorkerClient;
-
     var docs = {};
 
     docs.js = new EditSession(document.getElementById("jstext").innerHTML);
     docs.js.setMode(new JavaScriptMode());
     docs.js.setUndoManager(new UndoManager());
     
-    var worker = new WorkerClient("../..", ["ace", "pilot"], "ace/worker/mirror", "Mirror");
-    worker.call("setValue", [docs.js.getValue()]);
-    
-    docs.js.getDocument().on("change", function(e) {
-        e.range = {
-            start: e.data.range.start,
-            end: e.data.range.end
-        };
-        worker.emit("change", e);
-    });
+    if (false && window.Worker) {
+        var worker = new WorkerClient("../..", ["ace", "pilot"], "ace/worker/mirror", "Mirror");
+        worker.call("setValue", [docs.js.getValue()]);
         
-    worker.on("jslint", function(results) {
-        var errors = [];
-        for (var i=0; i<results.data.length; i++) {
-            var error = results.data[i];
-            if (error)
-                errors.push({
-                    row: error.line-1,
-                    column: error.character-1,
-                    text: error.reason,
-                    type: "error",
-                    lint: error
-                })
-        }
-                
-        docs.js.setAnnotations(errors)
-    });
-    
-    window.mirror = function() {
-        worker.call("getValue", [], function(value) {
-            console.log(value)
+        docs.js.getDocument().on("change", function(e) {
+            e.range = {
+                start: e.data.range.start,
+                end: e.data.range.end
+            };
+            worker.emit("change", e);
         });
-    }
-    
+            
+        worker.on("jslint", function(results) {
+            var errors = [];
+            for (var i=0; i<results.data.length; i++) {
+                var error = results.data[i];
+                if (error)
+                    errors.push({
+                        row: error.line-1,
+                        column: error.character-1,
+                        text: error.reason,
+                        type: "error",
+                        lint: error
+                    })
+            }
+                    
+            docs.js.setAnnotations(errors)
+        });
+    };
+        
     docs.css = new EditSession(document.getElementById("csstext").innerHTML);
     docs.css.setMode(new CssMode());
     docs.css.setUndoManager(new UndoManager());
diff --git a/lib/ace/edit_session.js b/lib/ace/edit_session.js
index c0c3c6ad..701cb543 100644
--- a/lib/ace/edit_session.js
+++ b/lib/ace/edit_session.js
@@ -52,16 +52,14 @@ var EditSession = function(text, mode) {
     this.selection = new Selection(this);
     this.$breakpoints = [];
 
-    this.listeners = [];
-    if (mode) {
-        this.setMode(mode);
-    }
-    
     if (text instanceof Document) {
         this.setDocument(text)
     } else {
         this.setDocument(new Document(text));
     }
+    
+    if (mode)
+        this.setMode(mode);
 };
 
 
@@ -288,6 +286,12 @@ var EditSession = function(text, mode) {
     this.setMode = function(mode) {
         if (this.$mode === mode) return;
 
+        if (this.$worker)
+            this.$worker.terminate();
+            
+        if (window.Worker)
+            this.$worker = mode.createWorker(this);
+
         this.$mode = mode;
         this._dispatchEvent("changeMode");
     };
diff --git a/lib/ace/mode/javascript.js b/lib/ace/mode/javascript.js
index 02f7e7ac..3d4d62d2 100644
--- a/lib/ace/mode/javascript.js
+++ b/lib/ace/mode/javascript.js
@@ -43,6 +43,7 @@ var Tokenizer = require("ace/tokenizer").Tokenizer;
 var JavaScriptHighlightRules = require("ace/mode/javascript_highlight_rules").JavaScriptHighlightRules;
 var MatchingBraceOutdent = require("ace/mode/matching_brace_outdent").MatchingBraceOutdent;
 var Range = require("ace/range").Range;
+var WorkerClient = require("ace/worker/worker_client").WorkerClient;
 
 var Mode = function() {
     this.$tokenizer = new Tokenizer(new JavaScriptHighlightRules().getRules());
@@ -120,6 +121,39 @@ oop.inherits(Mode, TextMode);
     this.autoOutdent = function(state, doc, row) {
         return this.$outdent.autoOutdent(doc, row);
     };
+    
+    this.createWorker = function(session) {
+        var doc = session.getDocument();
+        var worker = new WorkerClient("../..", ["ace", "pilot"], "ace/mode/javascript_worker", "JavaScriptWorker");
+        worker.call("setValue", [doc.getValue()]);
+        
+        doc.on("change", function(e) {
+            e.range = {
+                start: e.data.range.start,
+                end: e.data.range.end
+            };
+            worker.emit("change", e);
+        });
+            
+        worker.on("jslint", function(results) {
+            var errors = [];
+            for (var i=0; i<results.data.length; i++) {
+                var error = results.data[i];
+                if (error)
+                    errors.push({
+                        row: error.line-1,
+                        column: error.character-1,
+                        text: error.reason,
+                        type: "error",
+                        lint: error
+                    })
+            }
+                    
+            session.setAnnotations(errors)
+        });
+        
+        return worker;
+    };
 
 }).call(Mode.prototype);
 
diff --git a/lib/ace/mode/javascript_worker.js b/lib/ace/mode/javascript_worker.js
new file mode 100644
index 00000000..900f364c
--- /dev/null
+++ b/lib/ace/mode/javascript_worker.js
@@ -0,0 +1,24 @@
+
+define(function(require, exports, module) {
+    
+var oop = require("pilot/oop");
+var Mirror = require("ace/worker/mirror").Mirror;
+var lint = require("ace/worker/jslint").JSLINT;
+    
+var JavaScriptWorker = exports.JavaScriptWorker = function(sender) {
+    Mirror.call(this, sender);
+    this.setTimeout(500);
+};
+
+oop.inherits(JavaScriptWorker, Mirror);
+
+(function() {
+    
+    this.onUpdate = function() {
+        lint(this.doc.getValue(), {undef: false, onevar: false, passfail: false});
+        this.sender.emit("jslint", lint.errors);
+    }
+    
+}).call(JavaScriptWorker.prototype);
+
+});
\ No newline at end of file
diff --git a/lib/ace/mode/text.js b/lib/ace/mode/text.js
index 06a36733..7a400ef9 100644
--- a/lib/ace/mode/text.js
+++ b/lib/ace/mode/text.js
@@ -73,6 +73,10 @@ var Mode = function() {
 
         return "";
     };
+    
+    this.createWorker = function(session) {
+        return null;
+    };
 
 }).call(Mode.prototype);
 
diff --git a/lib/ace/worker/Demo.js b/lib/ace/worker/Demo.js
deleted file mode 100644
index 7d3b0689..00000000
--- a/lib/ace/worker/Demo.js
+++ /dev/null
@@ -1,16 +0,0 @@
-
-define(function(require, exports, module) {
-    
-var Demo = exports.Demo = function(sender) {
-    this.sender = sender;
-};
-
-(function() {
-    
-    this.juhu = function() {
-        console.log("JUHU")
-    }
-    
-}).call(Demo.prototype);
-
-});
\ No newline at end of file
diff --git a/lib/ace/worker/mirror.js b/lib/ace/worker/mirror.js
index 1ee2ad85..2d218998 100644
--- a/lib/ace/worker/mirror.js
+++ b/lib/ace/worker/mirror.js
@@ -2,7 +2,6 @@
 define(function(require, exports, module) {
     
 var Document = require("ace/document").Document;
-var lint = require("ace/worker/jslint").JSLINT;
 var lang = require("pilot/lang");
     
 var Mirror = exports.Mirror = function(sender) {
@@ -11,17 +10,24 @@ var Mirror = exports.Mirror = function(sender) {
     
     var deferredUpdate = this.deferredUpdate = lang.deferredCall(this.onUpdate.bind(this));
     
+    var _self = this;
     sender.on("change", function(e) {
         doc.applyDeltas([e.data]);        
-        deferredUpdate.schedule(500);
+        deferredUpdate.schedule(_self.$timeout);
     })
 };
 
 (function() {
     
+    this.$timeout = 500;
+    
+    this.setTimeout = function(timeout) {
+        this.$timeout = timeout;
+    };
+    
     this.setValue = function(value) {
         this.doc.setValue(value);
-        this.deferredUpdate.schedule(500);
+        this.deferredUpdate.schedule(this.$timeout);
     };
     
     this.getValue = function(callbackId) {
@@ -29,9 +35,8 @@ var Mirror = exports.Mirror = function(sender) {
     };
     
     this.onUpdate = function() {
-        lint(this.doc.getValue(), {undef: false, onevar: false, passfail: false});
-        this.sender.emit("jslint", lint.errors);
-    }
+        // abstract method
+    };
     
 }).call(Mirror.prototype);
 
diff --git a/lib/ace/worker/worker_client.js b/lib/ace/worker/worker_client.js
index c7dbd4e4..81a516a7 100644
--- a/lib/ace/worker/worker_client.js
+++ b/lib/ace/worker/worker_client.js
@@ -64,6 +64,10 @@ var WorkerClient = function(baseUrl, topLevelNamespaces, module, classname) {
 
     oop.implement(this, EventEmitter);
 
+    this.terminate = function() {
+        this.$worker.terminate();
+    };
+
     this.send = function(cmd, args) {
         this.$worker.postMessage({command: cmd, args: args});
     };