Yii 验证码验证

控制器如下

LoginForm如下

视图如下

<div class="loginbody">
            <span class="systemlogo"></span>
            <div class="loginbox">
                <ul>
                    <?php $form = $this->beginWidget('CActiveForm',array('method'=>'post'))?>
                        <li class="loginuser"><?php echo $form->textField($loginForm,'username',array('class'=>'loginuserinput','value'=>'user','onclick'=>'JavaScript:this.value=""',"size"=>"20"));?></li>
                        <li class="loginpwd"><?php echo $form->passwordField($loginForm,'password',array('class'=>'loginuserinput','value'=>'','onclick'=>'JavaScript:this.value=""',"size"=>"20"));?></li>
                        <li class="code"><?php echo $form->textField($loginForm,'captcha',array('class'=>'loginuserinput','value'=>'','onclick'=>'JavaScript:this.value=""',"size"=>"8"));?>
                        <div style="float:right;margin-right:64px;"><?php $this->widget('CCaptcha',array('showRefreshButton'=>false,'clickableImage'=>true,'imageOptions'=>array('alt'=>'点击换图','title'=>'点击换图','style'=>'cursor:pointer'))); ?></div></li>
                        <div class="clb"></div>
                        <li><input name="login" type="submit" class="loginbtn" value="登录" />&nbsp;&nbsp;&nbsp;&nbsp;<label><a href="#">忘记密码？</a></label></li>
                    <?php $this->endWidget();?>
                </ul>
            </div>
        </div>
    </body>
</html>
<script type="text/javascript">
$(function(){
    <?php if($form->error($loginForm,'password')){echo "alert('".str_replace('<div class="errorMessage">','',str_replace('</div>','',$form->error($loginForm,'password')))."');";}?>
    <?php if($form->error($loginForm,'username')){echo "alert('".str_replace('<div class="errorMessage">','',str_replace('</div>','',$form->error($loginForm,'username')))."');";}?>
    <?php if($form->error($loginForm,'captcha')){echo "alert('".str_replace('<div class="errorMessage">','',str_replace('</div>','',$form->error($loginForm,'captcha')))."');";}?>
});
</script>