<?php
if( isset( $_GET['q'] ) ){
$src = $_GET['q'] . ".html" ;
} else {
$src = "default_product.html" ;
}
?>
<iframe src="<?php echo $src ?>" width="100%" height="300">
<p>Your browser does not support iframes.</p>
</iframe>
<A href = "store.html[COLOR="red"]?url=some product.html[/COLOR]"></A>