diff --git a/app/protected/controllers/SiteController.php b/app/protected/controllers/SiteController.php
index 776c927..ab4b6c7 100644
--- a/app/protected/controllers/SiteController.php
+++ b/app/protected/controllers/SiteController.php
@@ -1,5 +1,8 @@
 <?php
 
+use app\models\LoginForm;
+use app\models\User;
+
 class SiteController extends \yii\web\Controller
 {
 	public function actionIndex()
@@ -9,10 +12,18 @@ class SiteController extends \yii\web\Controller
 
 	public function actionLogin()
 	{
-		echo $this->render('login');
-//		$user = app\models\User::findIdentity(100);
-//		Yii::$app->getUser()->login($user);
-//		Yii::$app->getResponse()->redirect(array('site/index'));
+		$model = new LoginForm();
+		if (isset($_POST[$model->formName()])) {
+			$model->attributes = $_POST[$model->formName()];
+			if ($model->validate()) {
+				$user = User::findByUsername($model->username);
+				Yii::$app->getUser()->login($user);
+				Yii::$app->getResponse()->redirect(array('site/index'));
+			}
+		}
+		echo $this->render('login', array(
+			'model' => $model,
+		));
 	}
 
 	public function actionLogout()
diff --git a/app/protected/models/LoginForm.php b/app/protected/models/LoginForm.php
index 7151bce..743f95d 100644
--- a/app/protected/models/LoginForm.php
+++ b/app/protected/models/LoginForm.php
@@ -30,7 +30,7 @@ class LoginForm extends Model
 	public function validatePassword()
 	{
 		$user = User::findByUsername($this->username);
-		if (!$user && $user->validatePassword($this->password)) {
+		if (!$user || !$user->validatePassword($this->password)) {
 			$this->addError('password', 'Incorrect username or password.');
 		}
 	}
diff --git a/app/protected/views/site/login.php b/app/protected/views/site/login.php
index 3178f14..54afed2 100644
--- a/app/protected/views/site/login.php
+++ b/app/protected/views/site/login.php
@@ -1,7 +1,25 @@
+<?php
+use yii\helpers\Html;
+
+/**
+ * @var yii\base\View $this
+ * @var yii\widgets\ActiveForm $form
+ * @var app\models\LoginForm $model
+ */
+?>
 <h1>Login</h1>
 
 <p>Please fill out the following fields to login:</p>
 
-<?php $form = $this->beginWidget('yii\widgets\ActiveForm', array('method' => 'put')); ?>
+<?php $form = $this->beginWidget('yii\widgets\ActiveForm'); ?>
+	<?php
+		$field = $form->beginField($model, 'username');
+		echo $field->label() . "\n" . $field->textInput() . "\n" . $field->error() . "\n";
+		$form->endField();
 
+		$field = $form->beginField($model, 'password');
+		echo $field->label() . "\n" . $field->textInput() . "\n" . $field->error() . "\n";
+		$form->endField();
+	?>
+	<?php echo Html::submitButton('Login'); ?>
 <?php $this->endWidget(); ?>
\ No newline at end of file
diff --git a/framework/helpers/base/Html.php b/framework/helpers/base/Html.php
index 110dad9..e89e197 100644
--- a/framework/helpers/base/Html.php
+++ b/framework/helpers/base/Html.php
@@ -415,18 +415,18 @@ class Html
 
 	/**
 	 * Generates a button tag.
-	 * @param string $name the name attribute. If it is null, the name attribute will not be generated.
-	 * @param string $value the value attribute. If it is null, the value attribute will not be generated.
 	 * @param string $content the content enclosed within the button tag. It will NOT be HTML-encoded.
 	 * Therefore you can pass in HTML code such as an image tag. If this is is coming from end users,
 	 * you should consider [[encode()]] it to prevent XSS attacks.
+	 * @param string $name the name attribute. If it is null, the name attribute will not be generated.
+	 * @param string $value the value attribute. If it is null, the value attribute will not be generated.
 	 * @param array $options the tag options in terms of name-value pairs. These will be rendered as
 	 * the attributes of the resulting tag. The values will be HTML-encoded using [[encode()]].
 	 * If a value is null, the corresponding attribute will not be rendered.
 	 * If the options does not contain "type", a "type" attribute with value "button" will be rendered.
 	 * @return string the generated button tag
 	 */
-	public static function button($name = null, $value = null, $content = 'Button', $options = array())
+	public static function button($content = 'Button', $name = null, $value = null, $options = array())
 	{
 		$options['name'] = $name;
 		$options['value'] = $value;
@@ -438,38 +438,38 @@ class Html
 
 	/**
 	 * Generates a submit button tag.
-	 * @param string $name the name attribute. If it is null, the name attribute will not be generated.
-	 * @param string $value the value attribute. If it is null, the value attribute will not be generated.
 	 * @param string $content the content enclosed within the button tag. It will NOT be HTML-encoded.
 	 * Therefore you can pass in HTML code such as an image tag. If this is is coming from end users,
 	 * you should consider [[encode()]] it to prevent XSS attacks.
+	 * @param string $name the name attribute. If it is null, the name attribute will not be generated.
+	 * @param string $value the value attribute. If it is null, the value attribute will not be generated.
 	 * @param array $options the tag options in terms of name-value pairs. These will be rendered as
 	 * the attributes of the resulting tag. The values will be HTML-encoded using [[encode()]].
 	 * If a value is null, the corresponding attribute will not be rendered.
 	 * @return string the generated submit button tag
 	 */
-	public static function submitButton($name = null, $value = null, $content = 'Submit', $options = array())
+	public static function submitButton($content = 'Submit', $name = null, $value = null, $options = array())
 	{
 		$options['type'] = 'submit';
-		return static::button($name, $value, $content, $options);
+		return static::button($content, $name, $value, $options);
 	}
 
 	/**
 	 * Generates a reset button tag.
-	 * @param string $name the name attribute. If it is null, the name attribute will not be generated.
-	 * @param string $value the value attribute. If it is null, the value attribute will not be generated.
 	 * @param string $content the content enclosed within the button tag. It will NOT be HTML-encoded.
 	 * Therefore you can pass in HTML code such as an image tag. If this is is coming from end users,
 	 * you should consider [[encode()]] it to prevent XSS attacks.
+	 * @param string $name the name attribute. If it is null, the name attribute will not be generated.
+	 * @param string $value the value attribute. If it is null, the value attribute will not be generated.
 	 * @param array $options the tag options in terms of name-value pairs. These will be rendered as
 	 * the attributes of the resulting tag. The values will be HTML-encoded using [[encode()]].
 	 * If a value is null, the corresponding attribute will not be rendered.
 	 * @return string the generated reset button tag
 	 */
-	public static function resetButton($name = null, $value = null, $content = 'Reset', $options = array())
+	public static function resetButton($content = 'Reset', $name = null, $value = null, $options = array())
 	{
 		$options['type'] = 'reset';
-		return static::button($name, $value, $content, $options);
+		return static::button($content, $name, $value, $options);
 	}
 
 	/**
diff --git a/framework/validators/RequiredValidator.php b/framework/validators/RequiredValidator.php
index 3b13eb3..f4746e6 100644
--- a/framework/validators/RequiredValidator.php
+++ b/framework/validators/RequiredValidator.php
@@ -47,7 +47,7 @@ class RequiredValidator extends Validator
 	{
 		parent::init();
 		if ($this->message === null) {
-			$this->message = $this->requiredValue === null ? Yii::t('yii|{attribute} is invalid.')
+			$this->message = $this->requiredValue === null ? Yii::t('yii|{attribute} cannot be blank.')
 				: Yii::t('yii|{attribute} must be "{requiredValue}".');
 		}
 	}
diff --git a/framework/widgets/ActiveField.php b/framework/widgets/ActiveField.php
index 50b9619..965f48a 100644
--- a/framework/widgets/ActiveField.php
+++ b/framework/widgets/ActiveField.php
@@ -35,6 +35,13 @@ class ActiveField extends Component
 	
 	public function begin()
 	{
+		if ($this->model->hasErrors($this->attribute)) {
+			if (isset($this->options['class'])) {
+				$this->options['class'] .= ' ' . $this->form->errorCssClass;
+			} else {
+				$this->options['class'] = $this->form->errorCssClass;
+			}
+		}
 		return Html::beginTag('div', $this->options);
 	}
 	
@@ -52,6 +59,9 @@ class ActiveField extends Component
 		$tag = isset($options['tag']) ? $options['tag'] : 'div';
 		unset($options['tag']);
 		$error = $this->model->getFirstError($attribute);
+		if ($error === null) {
+			$options['style'] = isset($options['style']) ? rtrim($options['style'], ';') . '; display:none' : 'display:none';
+		}
 		return Html::tag($tag, Html::encode($error), $options);
 	}
 
diff --git a/tests/unit/framework/helpers/HtmlTest.php b/tests/unit/framework/helpers/HtmlTest.php
index 4077043..a3d0e65 100644
--- a/tests/unit/framework/helpers/HtmlTest.php
+++ b/tests/unit/framework/helpers/HtmlTest.php
@@ -157,20 +157,20 @@ class HtmlTest extends \yii\test\TestCase
 	public function testButton()
 	{
 		$this->assertEquals('<button type="button">Button</button>', Html::button());
-		$this->assertEquals('<button type="button" name="test" value="value">content<></button>', Html::button('test', 'value', 'content<>'));
-		$this->assertEquals('<button type="submit" class="t" name="test" value="value">content<></button>', Html::button('test', 'value', 'content<>', array('type' => 'submit', 'class' => "t")));
+		$this->assertEquals('<button type="button" name="test" value="value">content<></button>', Html::button('content<>', 'test', 'value'));
+		$this->assertEquals('<button type="submit" class="t" name="test" value="value">content<></button>', Html::button('content<>', 'test', 'value', array('type' => 'submit', 'class' => "t")));
 	}
 
 	public function testSubmitButton()
 	{
 		$this->assertEquals('<button type="submit">Submit</button>', Html::submitButton());
-		$this->assertEquals('<button type="submit" class="t" name="test" value="value">content<></button>', Html::submitButton('test', 'value', 'content<>', array('class' => 't')));
+		$this->assertEquals('<button type="submit" class="t" name="test" value="value">content<></button>', Html::submitButton('content<>', 'test', 'value', array('class' => 't')));
 	}
 
 	public function testResetButton()
 	{
 		$this->assertEquals('<button type="reset">Reset</button>', Html::resetButton());
-		$this->assertEquals('<button type="reset" class="t" name="test" value="value">content<></button>', Html::resetButton('test', 'value', 'content<>', array('class' => 't')));
+		$this->assertEquals('<button type="reset" class="t" name="test" value="value">content<></button>', Html::resetButton('content<>', 'test', 'value', array('class' => 't')));
 	}
 
 	public function testInput()