diff --git a/web/app/models/HTML.php b/web/app/models/HTML.php
index f037f09..a361aef 100644
--- a/web/app/models/HTML.php
+++ b/web/app/models/HTML.php
@@ -144,8 +144,10 @@ class HTML {
 	
 	public static function purifier() {
 		$config = HTMLPurifier_Config::createDefault();
-		//$config->set('HTML.Doctype', 'HTML 4.01 Transitional');
-		$config->set('Cache.DefinitionImpl', null);
+		// $config->set('Cache.DefinitionImpl', null);
+		$config->set('HTML.DefinitionID', 'UOJ__HTML::purifier()');
+		$config->set('HTML.DefinitionRev', 1);
+		$config->set('Output.Newline', true);
 		$def = $config->getHTMLDefinition(true);
 		
 		$def->addElement('section', 'Block', 'Flow', 'Common');
@@ -155,6 +157,16 @@ class HTML {
 		$def->addElement('header',  'Block', 'Flow', 'Common');
 		$def->addElement('footer',  'Block', 'Flow', 'Common');
 		
+		$extra_allowed_html = [
+			'span' => ['data-realname' => 'Text', 'data-uoj-username' => 'Number'],
+		];
+
+		foreach ($extra_allowed_html as $element => $attributes) {
+			foreach ($attributes as $attribute => $type) {
+				$def->addAttribute($element, $attribute, $type);
+			}
+		}
+		
 		return new HTMLPurifier($config);
 	}
 
@@ -172,6 +184,7 @@ class HTML {
 			'small' => [],
 			'del' => [],
 			'br' => [],
+			'span' => ['data-realname' => 'Text', 'data-uoj-username' => 'Number'],
 		];
 
 		$config = HTMLPurifier_Config::createDefault();
@@ -181,7 +194,7 @@ class HTML {
 
 		foreach ($allowed_html as $element => $attributes) {
 			$allowed_elements[$element] = true;
-			foreach ($attributes as $attribute => $x) {
+			foreach ($attributes as $attribute => $type) {
 				$allowed_attributes["$element.$attribute"] = true;
 			}
 		}
@@ -189,6 +202,17 @@ class HTML {
 		$config->set('HTML.AllowedElements', $allowed_elements);
 		$config->set('HTML.AllowedAttributes', $allowed_attributes);
 
+		// $config->set('Cache.DefinitionImpl', null);
+		$config->set('HTML.DefinitionID', 'UOJ__HTML::purifier_inline()');
+		$config->set('HTML.DefinitionRev', 1);
+		$def = $config->getHTMLDefinition(true);
+
+		foreach ($allowed_html as $element => $attributes) {
+			foreach ($attributes as $attribute => $type) {
+				$def->addAttribute($element, $attribute, $type);
+			}
+		}
+
 		return new HTMLPurifier($config);
 	}
 
diff --git a/web/app/models/UOJMarkdown.php b/web/app/models/UOJMarkdown.php
index 641641d..64e2ded 100644
--- a/web/app/models/UOJMarkdown.php
+++ b/web/app/models/UOJMarkdown.php
@@ -54,16 +54,16 @@ class UOJMarkdown extends ParsedownMath {
 	// https://gist.github.com/ShNURoK42/b5ce8baa570975db487c
     protected function inlineUserMention($Excerpt) {
     	if (preg_match('/^@([^\s]+)/', $Excerpt['text'], $matches)) {
-    		if (validateUsername($matches[1]) && ($user = queryUser($matches[1]))) {
+    		if (validateUsername($matches[1]) && ($user = queryUser($matches[1])) && $user['usergroup'] != 'B') {
     			return [
     				'extent' => strlen($matches[0]),
     				'element' => [
-    					'name' => 'a',
+    					'name' => 'span',
     					'text' => '@' . $user['username'],
     					'attributes' => [
-    						'href' => '/user/' . $user['username'],
     						'class' => 'uoj-username',
     						'data-realname' => $user['realname'],
+							'data-uoj-username' => 1,
     					],
     				],
     			];
diff --git a/web/js/uoj.js b/web/js/uoj.js
index 68d543c..3c1f465 100644
--- a/web/js/uoj.js
+++ b/web/js/uoj.js
@@ -428,7 +428,7 @@ $(document).ready(function() {
 // highlight
 $.fn.uoj_highlight = function() {
 	return $(this).each(function() {
-		$(this).find("span.uoj-username").each(replaceWithHighlightUsername);
+		$(this).find("span.uoj-username, span[data-uoj-username]").each(replaceWithHighlightUsername);
 		$(this).find(".uoj-honor").uoj_honor();
 		$(this).find(".uoj-testcase").uoj_testcase();
 		$(this).find(".uoj-score").each(function() {