PHP过滤字符

<? php
$str   =   trim ( $_REQUEST [ ' content ' ]);
$str =   str_replace ( " " , " <br> " ,   $str );
function  uh( $str ) 
{ 
     $farr   =   array ( 
         " /s+/ " ,                                                                                              // 过滤多余的空白 
         " /<(/?)(script|i?frame|style|html|body|title|link|meta|?|%)([^>]*?)>/isU " ,    // 过滤 <script 等可能引入恶意内容或恶意改变显示布局的代码,如果不需要插入flash等,还可以加入<object的过滤 
         " /(<[^>]*)on[a-zA-Z]+s*=([^>]*>)/isU " ,                                        // 过滤javascript的on事件 
      
   ); 
    $tarr   =   array ( 
         "   " ,  
         " ＜/1/2/3＞ " ,             // 如果要直接清除不安全的标签，这里可以留空 
         " /1/2 " ,  
   ); 

   $str   =   preg_replace (  $farr , $tarr , $str ); 
    return   $str ; 
} 
$message = uh( $str )
     ?>