you can redirect using a meta-tag:
html: <meta http-equiv="refresh" content="3; URL=/urlgoeshere.url">
or
php: echo "<meta http-equiv=\"refresh\" content=\"3; URL=/urlgoeshere.url\">";
you can place meta-refresh in browser-body and it will still refresh the site (this might be considered bad html coding) the number after content=" defines the seconds to wait before redirecting. in your case:
if($_REQUEST['stype'] == "INTL"){
echo "<meta http-equiv=\"refresh\" content=\"3; URL=/isearch.php?".$_SERVER['QUERY_STRING']."\">";
}else{
echo "<meta http-equiv=\"refresh\" content=\"3; URL=/search.php?".$_SERVER['QUERY_STRING']."\">";
}
note: setting url like URL=foo.bar in page.php will redirect to page.phpfoobar, so you might want to use a / or . prefix
I hope this helped you :)