diff --git a/lib/base/dao/dao.class.php b/lib/base/dao/dao.class.php
index 4fa1e1efc0..011ae686fa 100644
--- a/lib/base/dao/dao.class.php
+++ b/lib/base/dao/dao.class.php
@@ -1608,6 +1608,24 @@ class baseSQL
      */
     public $conditionIsTrue = false;
 
+    /**
+     * 条件层级。
+     * The condition level.
+     *
+     * @var bool
+     * @access public;
+     */
+    public $conditionLevel = 0;
+
+    /**
+     * 条件结果，beginIF 中表达式的结果会存储到这个数组中。
+     * Store the result of the expression.
+     *
+     * @var bool
+     * @access public;
+     */
+    public $conditionResults = array();
+
     /**
      * WHERE条件嵌套小括号标记。
      * If in mark or not.
@@ -1920,7 +1938,9 @@ class baseSQL
     public function beginIF($condition)
     {
         $this->inCondition = true;
-        $this->conditionIsTrue = $condition;
+        $this->conditionLevel += 1;
+        $this->conditionResults[$this->conditionLevel] = $condition;
+        $this->conditionIsTrue = !in_array(false, $this->conditionResults);
         return $this;
     }
 
@@ -1933,6 +1953,14 @@ class baseSQL
      */
     public function fi()
     {
+        unset($this->conditionResults[$this->conditionLevel]);
+        $this->conditionLevel -= 1;
+        if($this->conditionLevel > 0)
+        {
+            $this->conditionIsTrue = !in_array(false, $this->conditionResults);
+            return $this;
+        }
+
         $this->inCondition = false;
         $this->conditionIsTrue = false;
         return $this;
@@ -1961,7 +1989,7 @@ class baseSQL
         }
         else
         {
-            $condition = ctype_alnum((string)$arg1) ? '`' . $arg1 . '`' : $arg1;
+            $condition = (is_string($arg1) && ctype_alnum($arg1)) ? '`' . $arg1 . '`' : $arg1;
         }
 
         if(!$this->inMark) $this->sql .= ' ' . DAO::WHERE ." $condition ";
@@ -1980,7 +2008,7 @@ class baseSQL
     public function andWhere($condition, $addMark = false)
     {
         if($this->inCondition and !$this->conditionIsTrue) return $this;
-        if(ctype_alnum((string)$condition)) $condition = '`' . $condition . '`';
+        if(is_string($condition) && ctype_alnum($condition)) $condition = '`' . $condition . '`';
 
         $mark = $addMark ? '(' : '';
         $this->sql .= " AND {$mark} $condition ";
@@ -1998,7 +2026,7 @@ class baseSQL
     public function orWhere($condition)
     {
         if($this->inCondition and !$this->conditionIsTrue) return $this;
-        if(ctype_alnum((string)$condition)) $condition = '`' . $condition . '`';
+        if(is_string($condition) && ctype_alnum($condition)) $condition = '`' . $condition . '`';
 
         $this->sql .= " OR $condition ";
         return $this;
diff --git a/lib/base/front/front.class.php b/lib/base/front/front.class.php
index ae59ad0497..1986a5118e 100644
--- a/lib/base/front/front.class.php
+++ b/lib/base/front/front.class.php
@@ -573,7 +573,14 @@ class baseHTML
             }
         }
 
-        return "<a href='{$gobackLink}' class='btn btn-back $class' $misc>{$label}</a>";
+        $button = "<a href='{$gobackLink}' class='btn btn-back $class' $misc>{$label}</a>";
+
+        $app->loadClass('purifier', true);
+        $purifierConfig   = HTMLPurifier_Config::createDefault();
+        $purifierConfig->set('Cache.DefinitionImpl', null);
+        $purifier = new HTMLPurifier($purifierConfig);
+
+        return $purifier->purify($button);
     }
 
     /**