Simple and easy to understand php sql anti-injection code

//Illegal characters to be filtered
$ArrFiltrate=array("'",";","union");
//The url to be redirected after an error occurs, if not filled in Default previous page
$StrGoUrl="";
//Whether there is a value in the array
function FunStringExist($StrFiltrate,$ArrFiltrate){
foreach ($ArrFiltrate as $key=>$value){
if (eregi ($value,$StrFiltrate)){
return true;
}
}
return false;
}
//Merge $_POST and $_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;
}
}
//Verification starts
foreach($ArrPostAndGet as $key=>$value){
if (FunStringExist($value,$ArrFiltrate)){
echo “< script language=”javascript”>alert(“Illegal character”);”;
if (emptyempty($StrGoUrl)){
echo “”;
}else{
echo “”;
}
exit;
}
}
?>

Method 2

/* Filter all GET variables*/
foreach ($_GET as $get_key=>$get_var)
{
if (is_numeric($get_var)) {
$get[ strtolower($get_key)] = get_int($get_var);
} else {
$get[strtolower($get_key)] = get_str($get_var);
}
}
/* Filter all POST variables*/
 foreach ($_POST as $post_key=>$post_var)
{
if (is_numeric($post_var)) {
$post[strtolower($post_key)] = get_int($post_var);
} else {
$post[ strtolower($post_key)] = get_str($post_var);
}
}
/* Filter function*/
//Integer filter function
function get_int($number)
{
return intval($number);
}
//String filter function
function get_str($string)
{
if (!get_magic_quotes_gpc()) {
return addslashes($string);
}
return $string;
}
?>