if (screen.width == 800) {
    document.write('<link rel="stylesheet" type="text/css" href="css/800.css">');
    }
    else if (screen.width == 1024) {
    document.write('<link rel="stylesheet" type="text/css" href="css/1024.css">');
    }
    else if (screen.width == 1280) {
    document.write('<link rel="stylesheet" type="text/css" href="css/1280.css">');
    }
    else if (screen.width == 1600) {
    document.write('<link rel="stylesheet" type="text/css" href="css/1600.css">');
    }
    else {
    document.write('<link rel="stylesheet" type="text/css" href="css/1024e.css">');
    }