//要过滤的非法字符
$ArrFiltrate=array("'",";","union");
//出错后要跳转的url,不填则默认前一页
$StrGoUrl="";
//是否存在数组中的值
function FunStringExist($StrFiltrate,$ArrFiltrate){
foreach ($ArrFiltrate as $key=>$value){
if (eregi($value,$StrFiltrate)){
return true;
}
}
return false;
}

//合并$_POST 和 $_GET
if(function_exists(array_merge)){
$ArrPostAndGet=array_merge($HTTP_POST_VARS,$HTTP_GET_VARS);
}else{
foreach($HTTP_POST_VARS as $key=>$value){
$ArrPostAndGet[]=$value;
}
foreach($HTTP_GET_VARS as $key=>$value){
$ArrPostAndGet[]=$value;
}
}

//验证开始
foreach($ArrPostAndGet as $key=>$value){
if (FunStringExist($value,$ArrFiltrate)){
echo " ";
if (empty($StrGoUrl)){
echo " ";
}else{
echo " ";
}
exit;
}
}
?>

保存为checkpostandget.php
然后在每个php文件前加include(“checkpostandget.php“);即可