if (screen.availWidth <= 640) { document.writeln(''); } else if (screen.availWidth <= 800) { document.writeln(''); } else if (screen.availWidth <= 1024) { document.writeln(''); } else if (screen.availWidth <= 1152) { document.writeln(''); } else if (screen.availWidth <= 1280) { document.writeln(''); } else { document.writeln(''); }