diff --git a/apps/advanced/.bowerrc b/apps/advanced/.bowerrc
new file mode 100644
index 0000000..3f8ac64
--- /dev/null
+++ b/apps/advanced/.bowerrc
@@ -0,0 +1,3 @@
+{
+    "directory" : "assets"
+}
diff --git a/apps/advanced/backend/web/assets/.gitkeep b/apps/advanced/assets/.gitkeep
similarity index 100%
rename from apps/advanced/backend/web/assets/.gitkeep
rename to apps/advanced/assets/.gitkeep
diff --git a/apps/advanced/backend/.bowerrc b/apps/advanced/backend/.bowerrc
deleted file mode 100644
index 16098e9..0000000
--- a/apps/advanced/backend/.bowerrc
+++ /dev/null
@@ -1,3 +0,0 @@
-{
-    "directory" : "web/assets"
-}
\ No newline at end of file
diff --git a/apps/advanced/backend/bower.json b/apps/advanced/bower.json
similarity index 70%
rename from apps/advanced/backend/bower.json
rename to apps/advanced/bower.json
index 4e165e6..63b1246 100644
--- a/apps/advanced/backend/bower.json
+++ b/apps/advanced/bower.json
@@ -1,5 +1,5 @@
 {
-    "name": "yii2-advanced-backend",
+    "name": "yii2-advanced",
     "version": "1.0.0",
     "dependencies": {
     },
diff --git a/apps/advanced/environments/index.php b/apps/advanced/environments/index.php
index e7ab700..1bec659 100644
--- a/apps/advanced/environments/index.php
+++ b/apps/advanced/environments/index.php
@@ -18,6 +18,9 @@
  *         'setCookieValidationKey' => [
  *             // list of config files that need to be inserted with automatically generated cookie validation keys
  *         ],
+ *         'createSymlink' => [
+ *             // list of symlinks to be created. Keys are symlinks, and values are the targets.
+ *         ],
  *     ],
  * ];
  * ```
@@ -38,6 +41,10 @@ return [
             'backend/config/main-local.php',
             'frontend/config/main-local.php',
         ],
+        'createSymlink' => [
+            'frontend/web/assets' => 'assets',
+            'backend/web/assets' => 'assets',
+        ],
     ],
     'Production' => [
         'path' => 'prod',
@@ -54,5 +61,9 @@ return [
             'backend/config/main-local.php',
             'frontend/config/main-local.php',
         ],
+        'createSymlink' => [
+            'frontend/web/assets' => 'assets',
+            'backend/web/assets' => 'assets',
+        ],
     ],
 ];
diff --git a/apps/advanced/frontend/.bowerrc b/apps/advanced/frontend/.bowerrc
deleted file mode 100644
index 16098e9..0000000
--- a/apps/advanced/frontend/.bowerrc
+++ /dev/null
@@ -1,3 +0,0 @@
-{
-    "directory" : "web/assets"
-}
\ No newline at end of file
diff --git a/apps/advanced/frontend/bower.json b/apps/advanced/frontend/bower.json
deleted file mode 100644
index cad1f7e..0000000
--- a/apps/advanced/frontend/bower.json
+++ /dev/null
@@ -1,8 +0,0 @@
-{
-    "name": "yii2-advanced-frontend",
-    "version": "1.0.0",
-    "dependencies": {
-    },
-    "devDependencies": {
-    }
-}
diff --git a/apps/advanced/frontend/web/assets/.gitkeep b/apps/advanced/frontend/web/assets/.gitkeep
deleted file mode 100644
index 72e8ffc..0000000
--- a/apps/advanced/frontend/web/assets/.gitkeep
+++ /dev/null
@@ -1 +0,0 @@
-*
diff --git a/apps/advanced/init b/apps/advanced/init
index db9dd7e..e6278db 100755
--- a/apps/advanced/init
+++ b/apps/advanced/init
@@ -193,3 +193,13 @@ function setCookieValidationKey($root, $paths)
         file_put_contents($file, $content);
     }
 }
+
+function createSymlink($links)
+{
+    foreach ($links as $link => $target) {
+        echo "    symlink $target as $link\n";
+        if (!is_link($link)) {
+            symlink($target, $link);
+        }
+    }
+}
diff --git a/extensions/jui/DatePicker.php b/extensions/jui/DatePicker.php
index fbdd836..bf2e186 100644
--- a/extensions/jui/DatePicker.php
+++ b/extensions/jui/DatePicker.php
@@ -78,22 +78,27 @@ class DatePicker extends InputWidget
     public function run()
     {
         echo $this->renderWidget() . "\n";
+
         $containerID = $this->inline ? $this->containerOptions['id'] : $this->options['id'];
         $language = $this->language ? $this->language : Yii::$app->language;
+
         if ($language != 'en-US') {
             $view = $this->getView();
-            DatePickerLanguageAsset::register($view);
-
+            $bundle = DatePickerLanguageAsset::register($view);
+            if ($bundle->autoGenerate) {
+                $am = $view->getAssetManager();
+                $view->registerJsFile($am->getAssetUrl("jquery-ui/ui/i18n/datepicker-$language.js"), [
+                    'depends' => [JuiAsset::className()],
+                ]);
+            }
             $options = Json::encode($this->clientOptions);
             $view->registerJs("$('#{$containerID}').datepicker($.extend({}, $.datepicker.regional['{$language}'], $options));");
-
-            $options = $this->clientOptions;
-            $this->clientOptions = false; // the datepicker js widget is already registered
-            $this->registerWidget('datepicker', $containerID);
-            $this->clientOptions = $options;
         } else {
-            $this->registerWidget('datepicker', $containerID);
+            $this->registerClientOptions('datepicker', $containerID);
         }
+
+        $this->registerClientEvents('datepicker', $containerID);
+        JuiAsset::register($this->getView());
     }
 
     /**
diff --git a/extensions/jui/DatePickerLanguageAsset.php b/extensions/jui/DatePickerLanguageAsset.php
index 0c1ecf0..9f9cdf4 100644
--- a/extensions/jui/DatePickerLanguageAsset.php
+++ b/extensions/jui/DatePickerLanguageAsset.php
@@ -15,9 +15,15 @@ use yii\web\AssetBundle;
  */
 class DatePickerLanguageAsset extends AssetBundle
 {
-    public $js = [
-        'jquery.ui.datepicker-i18n.js',
-    ];
+    /**
+     * @var boolean whether to automatically generate the needed language js files.
+     * If this is true, the language js files will be determined based on the actual usage of [[DatePicker]]
+     * and its language settings. If this is false, you should explicitly specify the language js files via [[js]].
+     */
+    public $autoGenerate = true;
+    /**
+     * @inheritdoc
+     */
     public $depends = [
         'yii\jui\JuiAsset',
     ];
diff --git a/framework/web/AssetBundle.php b/framework/web/AssetBundle.php
index b37ed8e..0f905a3 100644
--- a/framework/web/AssetBundle.php
+++ b/framework/web/AssetBundle.php
@@ -9,6 +9,7 @@ namespace yii\web;
 
 use Yii;
 use yii\base\Object;
+use yii\helpers\Url;
 
 /**
  * AssetBundle represents a collection of asset files, such as CSS, JS, images.
@@ -115,4 +116,61 @@ class AssetBundle extends Object
             $this->baseUrl = rtrim(Yii::getAlias($this->baseUrl), '/');
         }
     }
+
+    /**
+     * @param View $view
+     */
+    public function registerAssetFiles($view)
+    {
+        $manager = $view->getAssetManager();
+        foreach ($this->js as $js) {
+            $view->registerJsFile($this->getAssetUrl($js, $manager), $this->jsOptions);
+        }
+        foreach ($this->css as $css) {
+            $view->registerCssFile($this->getAssetUrl($css, $manager), $this->cssOptions);
+        }
+    }
+
+    /**
+     * Returns the actual URL for the specified asset.
+     * The actual URL is obtained by prepending either [[baseUrl]] or [[AssetManager::baseUrl]] to the given asset path.
+     * @param string $asset the asset path. This should be one of the assets listed in [[js]] or [[css]].
+     * @param AssetManager $manager the asset manager
+     * @return string the actual URL for the specified asset.
+     */
+    protected function getAssetUrl($asset, $manager)
+    {
+        if (($actualAsset = $manager->resolveAsset($asset)) !== false) {
+            return Url::isRelative($actualAsset) ? $manager->baseUrl . '/' . $actualAsset : $actualAsset;
+        }
+
+        if (strncmp($asset, '@/', 2) === 0) {
+            return $manager->baseUrl . substr($asset, 1);
+        } elseif (Url::isRelative($asset)) {
+            return $this->baseUrl . '/' . $asset;
+        } else {
+            return $asset;
+        }
+    }
+
+    /**
+     * Returns the actual file path for the specified asset.
+     * @param string $asset the asset path. This should be one of the assets listed in [[js]] or [[css]].
+     * @param AssetManager $manager the asset manager
+     * @return string|boolean the actual file path, or false if the asset is specified as an absolute URL
+     */
+    public function getAssetPath($asset, $manager)
+    {
+        if (($actualAsset = $manager->resolveAsset($asset)) !== false) {
+            return Url::isRelative($actualAsset) ? $manager->basePath . '/' . $actualAsset : false;
+        }
+
+        if (strncmp($asset, '@/', 2) === 0) {
+            return $manager->basePath . substr($asset, 1);
+        } elseif (Url::isRelative($asset)) {
+            return $this->basePath . '/' . $asset;
+        } else {
+            return false;
+        }
+    }
 }
diff --git a/framework/web/AssetManager.php b/framework/web/AssetManager.php
index 225a1db..925f3a2 100644
--- a/framework/web/AssetManager.php
+++ b/framework/web/AssetManager.php
@@ -10,7 +10,6 @@ namespace yii\web;
 use Yii;
 use yii\base\Component;
 use yii\base\InvalidConfigException;
-use yii\helpers\Url;
 
 /**
  * AssetManager manages asset bundle configuration and loading.
@@ -84,6 +83,8 @@ class AssetManager extends Component
      */
     public $assetMap = [];
 
+    private $_dummyBundles = [];
+
 
     /**
      * Initializes the component.
@@ -114,7 +115,7 @@ class AssetManager extends Component
     public function getBundle($name)
     {
         if ($this->bundles === false) {
-            return null;
+            return $this->loadDummyBundle($name);
         } elseif (!isset($this->bundles[$name])) {
             return $this->bundles[$name] = $this->loadBundle($name);
         } elseif ($this->bundles[$name] instanceof AssetBundle) {
@@ -122,7 +123,7 @@ class AssetManager extends Component
         } elseif (is_array($this->bundles[$name])) {
             return $this->bundles[$name] = $this->loadBundle($name, $this->bundles[$name]);
         } elseif ($this->bundles[$name] === false) {
-            return null;
+            return $this->loadDummyBundle($name);
         } else {
             throw new InvalidConfigException("Invalid asset bundle configuration: $name");
         }
@@ -143,49 +144,42 @@ class AssetManager extends Component
         return $bundle;
     }
 
-    /**
-     * @param View $view
-     * @param AssetBundle $bundle
-     */
-    public function registerAssetFiles($view, $bundle)
+    protected function loadDummyBundle($name)
     {
-        foreach ($bundle->js as $js) {
-            $view->registerJsFile($this->getAssetUrl($bundle, $js), $bundle->jsOptions);
-        }
-        foreach ($bundle->css as $css) {
-            $view->registerCssFile($this->getAssetUrl($bundle, $css), $bundle->cssOptions);
+        if (!isset($this->_dummyBundles[$name])) {
+            $this->_dummyBundles[$name] = $this->loadBundle($name, [
+                'js' => [],
+                'css' => [],
+                'depends' => [],
+            ]);
         }
+        return $this->_dummyBundles[$name];
     }
 
-    protected function getAssetUrl($bundle, $file)
+    public function resolveAsset($asset)
     {
-        if (($mappedFile = $this->mapAsset($file)) !== false) {
-            return Url::isRelative($mappedFile) ? $this->baseUrl . '/' . $mappedFile : $mappedFile;
+        if (isset($this->assetMap[$asset])) {
+            return $this->assetMap[$asset];
         }
 
-        if (strncmp($file, '@/', 2) === 0) {
-            $file = $this->baseUrl . substr($file, 1);
-        } elseif (Url::isRelative($file)) {
-            $file = $bundle->baseUrl . '/' . $file;
-        }
-
-        return $file;
-    }
-
-    protected function mapAsset($file)
-    {
-        if (isset($this->assetMap[$file])) {
-            return $this->assetMap[$file];
-        }
-
-        $n = strlen($file);
+        $n = strlen($asset);
         foreach ($this->assetMap as $from => $to) {
             $n2 = strlen($from);
-            if ($n2 <= $n && substr_compare($file, $from, $n - $n2, $n2) === 0) {
+            if ($n2 <= $n && substr_compare($asset, $from, $n - $n2, $n2) === 0) {
                 return $to;
             }
         }
 
         return false;
     }
+
+    public function getAssetUrl($asset)
+    {
+        return $this->baseUrl . '/' . ltrim($asset, '/');
+    }
+
+    public function getAssetPath($asset)
+    {
+        return $this->basePath . '/' . ltrim($asset, '/');
+    }
 }
diff --git a/framework/web/View.php b/framework/web/View.php
index c1ce75a..7733068 100644
--- a/framework/web/View.php
+++ b/framework/web/View.php
@@ -261,7 +261,7 @@ class View extends \yii\base\View
             foreach ($bundle->depends as $dep) {
                 $this->registerAssetFiles($dep);
             }
-            $this->getAssetManager()->registerAssetFiles($this, $bundle);
+            $bundle->registerAssetFiles($this);
         }
         unset($this->assetBundles[$name]);
     }
@@ -380,7 +380,7 @@ class View extends \yii\base\View
         } else {
             $this->getAssetManager()->bundles[$key] = new AssetBundle([
                 'baseUrl' => '',
-                'css' => [$url],
+                'css' => [ltrim($url, '/')],
                 'cssOptions' => $options,
                 'depends' => (array) $depends,
             ]);
@@ -445,7 +445,7 @@ class View extends \yii\base\View
         } else {
             $this->getAssetManager()->bundles[$key] = new AssetBundle([
                 'baseUrl' => '',
-                'js' => [$url],
+                'js' => [ltrim($url, '/')],
                 'jsOptions' => $options,
                 'depends' => (array) $depends,
             ]);