php 防注入攻击函数

/*php 防注入函数
string  $feifa  限制元素组成
如有非法字符跳转到上一页 返回 0  没有返回 1
*/
//使用方法
//$feifa=array("select","delete","from","update","create","destory","drop","alter","and","or","like","exec","count","*","chr","mid","master","truncate","char","declare",";","-","+");
//$arrpostget=array("http://www.baidu.select cretecomdmin","wangw");
//echo saftsql($feifa,$arrpostget);
function saftsql($feifa,$arrpostget){
//
$arrpostget=array_merge((array)$HTTP_PSOT_VARS,(array)$HTTP_GET_VARS);
  if($arrpostget){
         foreach($arrpostget as $key=>$value){
              for($i=0;$i<count($feifa);$i++){
                //找非法字符在$value中的位置
                $flag=strpos($value,$feifa[$i]);              
                if($flag)
                {                    
                 echo "<script
type=\"text/javascript\">alert('URL有非法字符');</script>";