//mysql connection
 
 
$objcatId = new catId();
$rsId[] = explode(",",$objcatId->prod_view(22));
print_r($rsId);
 
class catId{
 
static $idvalues="";
 
function prod_view($id)
{
 
	$sql = mysql_query("select id from cart_category where pid='$id'") or die(mysql_error());
	$num = mysql_num_rows($sql);
 
	if($num > 0)
	{
 
		while($row = mysql_fetch_array($sql))
		{
			if(self::$idvalues=="")
			{
				self::$idvalues=$row['id'];
			}
			else
			{
				self::$idvalues.=",".$row['id'];
			}
 
			$this->prod_view($row['id']);
 
		}
 
	}
 
	return self::$idvalues;
} 
 
}