PHP universal anti-injection program recommended_PHP tutorial

function jk1986_checksql()
{
$bad_str = "and|select|update| '|delete|insert|*";
$bad_Array = explode("|",$bad_str);
/**Filter Get parameters **/
foreach ($bad_Array as $bad_a)
{
foreach ($_GET as $g)
{
if (substr_count(strtolower($g),$bad_a) > 0)
{
echo "<script>alert ('Weird characters, please do not try to inject them into this site! Author: Jk1986 QQ:414028660'); location.href='index.php';</script>";
exit();
}
}
}

/**Filter Post parameters **/

foreach ($bad_Array as $bad_a)
{
foreach ($_POST as $p)
{
if (substr_count(strtolower($p),$bad_a) > 0)
{
echo "<script>alert('Weird characters, please do not try to inject them into this site! Author:Jk1986 QQ:414028660');location.href='index.php';</script>";
exit();
}
}
}

/**Filter Cookies Parameters **/

foreach ($bad_Array as $bad_a)
{
foreach ($_COOKIE as $co)
{
if (substr_count(strtolower ($co),$bad_a) > 0)
{
echo "<script>alert('Weird characters, please do not try to inject them into this site! Author: Jk1986 QQ:414028660'); location.href ='index.php';</script>";
exit();
}
}
}
}