// small example if (is_browser('ie') OR is_browser('mozilla')) { $banner_width = 468; $banner_height = 60; } else { $banner_width = 234; $banner_height = 30; } $banner_advert = "<img src=\"http://www.domain.com/wherever/advert.gif\" width=\"".$banner_width."\" height=\"".$banner_height."\" border=\"0\">";