if (screen.width<=800||screen.height<=600)
document.write('<link rel="StyleSheet" href="css/lowres.css" type="text/css" media="screen"/>')

else if (screen.width>=1280||screen.height>=1024)
document.write('<link rel="StyleSheet" href="css/highres.css" type="text/css" media="screen"/>')

else
document.write('<link rel="StyleSheet" href="css/style.css" type="text/css" media="screen"/>')