diff --git a/plugin-captcha/action.php b/plugin-captcha/action.php
index ea728a2..d6e71ca 100755
--- a/plugin-captcha/action.php
+++ b/plugin-captcha/action.php
@@ -53,8 +53,37 @@ class action_plugin_captcha extends DokuWiki_Action_Plugin {
                                        'handle_editform_output',
                                        array('editform' => false, 'oldhook' => false));
         }
+		
+		if($this->getConf('loginprotect')){
+            $controller->register_hook('AUTH_LOGIN_CHECK',
+                                       'BEFORE',
+                                       $this,
+                                       'handle_loginform_check',
+                                       array('editform' => false, 'oldhook' => false));
+			
+			$controller->register_hook('HTML_LOGINFORM_OUTPUT',
+                                       'BEFORE',
+                                       $this,
+                                       'handle_editform_output',
+                                       array('editform' => false, 'oldhook' => false));
+
+        }
     }
 
+	/** 
+	 * Check captcha of login form
+	 */
+	function handle_loginform_check(&$event, $param){
+		if(!('login' == $_POST['do'] && $this->getConf('loginprotect'))) {
+			return;
+		}
+		
+		$helper = plugin_load('helper','captcha');
+        if(!$helper->check()){
+			$event->preventDefault();
+		}
+	}
+	
     /**
      * Will intercept the 'save' action and check for CAPTCHA first.
      */
diff --git a/plugin-captcha/conf/default.php b/plugin-captcha/conf/default.php
index 6c667a4..7d1eafb 100755
--- a/plugin-captcha/conf/default.php
+++ b/plugin-captcha/conf/default.php
@@ -8,5 +8,6 @@
 $conf['mode']       = 'js';
 $conf['forusers']   = 0;
 $conf['regprotect'] = 1;
+$conf['loginprotect'] = 1;
 $conf['width']      = 115;
 $conf['height']     = 22;
diff --git a/plugin-captcha/conf/metadata.php b/plugin-captcha/conf/metadata.php
index 8b28944..eab3663 100755
--- a/plugin-captcha/conf/metadata.php
+++ b/plugin-captcha/conf/metadata.php
@@ -6,6 +6,7 @@
  */
 
 $meta['mode']       = array('multichoice','_choices' => array('js','text','image','audio','figlet'));
+$meta['loginprotect'] = array('onoff');
 $meta['regprotect'] = array('onoff');
 $meta['forusers']   = array('onoff');
 $meta['width']      = array('numeric','_pattern' => '/[0-9]+/');
diff --git a/plugin-captcha/helper.php b/plugin-captcha/helper.php
index 56e84bd..6a4c0cb 100755
--- a/plugin-captcha/helper.php
+++ b/plugin-captcha/helper.php
@@ -97,8 +97,9 @@ class helper_plugin_captcha extends DokuWiki_Plugin {
      * page revision.
      */
     function _fixedIdent(){
-        global $ID;
-        $lm = @filemtime(wikiFN($ID));
+        //global $ID;
+        $ID = getID();  // use getID instead
+		$lm = @filemtime(wikiFN($ID));
         return auth_browseruid().
                auth_cookiesalt().
                $ID.$lm;
diff --git a/plugin-captcha/lang/en/settings.php b/plugin-captcha/lang/en/settings.php
index 8b39b87..07ec4af 100755
--- a/plugin-captcha/lang/en/settings.php
+++ b/plugin-captcha/lang/en/settings.php
@@ -12,6 +12,7 @@ $lang['mode_o_image']  = "Image (bad accessibility)";
 $lang['mode_o_audio']  = "Image+Audio (better accessibility)";
 $lang['mode_o_figlet'] = "Figlet ASCII Art (bad accessibility)";
 
+$lang['loginprotect'] = "Protect the login form as well?";
 $lang['regprotect'] = "Protect the registration form as well?";
 $lang['forusers']   = "Use CAPTCHA for logged in users, too?";
 $lang['width']      = "Width of the CAPTCHA image (pixel)";
diff --git a/plugin-captcha/lang/zh/lang.php b/plugin-captcha/lang/zh/lang.php
index e5bf609..7541c50 100755
--- a/plugin-captcha/lang/zh/lang.php
+++ b/plugin-captcha/lang/zh/lang.php
@@ -6,6 +6,6 @@
  */
 
 $lang['testfailed']  = "抱歉，您输入的验证码不正确。";
-$lang['fillcaptcha'] = "请在输入框中填入验证码以证明您不是机器人。";
+$lang['fillcaptcha'] = "请输入右边的验证码";
 $lang['soundlink']   = "如果您无法阅读图片中的字母，请下载此 .wav 文件。";
 
diff --git a/plugin-captcha/lang/zh/settings.php b/plugin-captcha/lang/zh/settings.php
index 9581650..1180c22 100755
--- a/plugin-captcha/lang/zh/settings.php
+++ b/plugin-captcha/lang/zh/settings.php
@@ -12,6 +12,7 @@ $lang['mode_o_image']  = "图片 (无障碍性差)";
 $lang['mode_o_audio']  = "图片+音频 (更好的无障碍性)";
 $lang['mode_o_figlet'] = "Figlet ASCII 艺术 (无障碍性差)";
 
+$lang['loginprotect'] = "同时保护登录表单吗?";
 $lang['regprotect'] = "同时保护注册表单吗？";
 $lang['forusers']   = "对已登入的用户也适用吗？";
 $lang['width']      = "验证码图片宽度 (像素)";