diff --git a/pyjaco/todoy.py b/pyjaco/todoy.py
new file mode 100644
index 0000000..c9bf0f9
--- /dev/null
+++ b/pyjaco/todoy.py
@@ -0,0 +1,25 @@
+
+def setup():
+    validate("#registration_form",
+        {
+        'confirm_password': 'The passwords do not match',
+        'username': "I'm afraid that username is taken"},
+        username={
+            'required': True,
+            'remote': 'user_valid.json'
+        },
+        password='required',
+        confirm_password={'equalTo': 'input[name=password]'})
+
+
+@JSVar('jQuery')
+def validate(selector, mess=None, **kwargs):
+    if mess == None:
+        mess = {}
+    jQuery(js(selector)).validate(
+        {'rules': js(kwargs),
+        'messages': js(mess)
+        }
+        )
+
+jQuery(js(setup))
diff --git a/www/account/register.html b/www/account/register.html
index de65d8e..92aa281 100644
--- a/www/account/register.html
+++ b/www/account/register.html
@@ -1,5 +1,4 @@
 # -*- python -*-
-import json
 from aspen import Response
 from trembling.auth import User
 from trembling import Redirect
@@ -46,7 +45,7 @@
     except InvalidDataError as e:
         print e.error_dict()
         response = Response(406, json.dumps(
-            {k:v.message for k,v in e.error_dict().iteritems()}))
+            {k: v.message for k, v in e.error_dict().iteritems()}))
     else:
         print "VALID"
 
diff --git a/www/account/user_valid.json b/www/account/user_valid.json
new file mode 100644
index 0000000..8f7c49b
--- /dev/null
+++ b/www/account/user_valid.json
@@ -0,0 +1,15 @@
+# -*- python -*-
+# This json response is used by the validator on
+# register.html
+from aspen import Response
+from trembling.auth import User
+
+^L
+username = request.qs.one('username')
+existing_user = User.objects(username=username)
+
+response = Response()
+if existing_user:
+    response.body = False
+else:
+    response.body = True
diff --git a/www/js/todoy.js b/www/js/todoy.js
index 4bf246e..892e9ab 100644
--- a/www/js/todoy.js
+++ b/www/js/todoy.js
@@ -2,7 +2,7 @@ var setup = function() {
     var __kwargs = __kwargs_get(arguments);
     var __varargs = __varargs_get(arguments);
     var $v1 = Array.prototype.slice.call(arguments).concat(js(__varargs));
-    validate(str('#registration_form'), dict([str('confirm_password'), str('The passwords do not match')]), __kwargs_make({username: str('required'), password: str('required'), confirm_password: dict([str('equalTo'), str('input[name=password]')])}));
+    validate(str('#registration_form'), dict([str('confirm_password'), str('The passwords do not match'), str('username'), str("I'm afraid that username is taken")]), __kwargs_make({username: dict([str('required'), __builtins__.PY$True, str('remote'), str('user_valid.json')]), password: str('required'), confirm_password: dict([str('equalTo'), str('input[name=password]')])}));
 return None;
 }
 var validate = function() {