if (screen.width < 1152) {

}
if ((screen.width >=1152) && (screen.width <1280)){
document.write('<link rel="stylesheet" href="fileadmin/template/res/stylesheet1152.css" type="text/css" />');
}
if ((screen.width >=1280) && (screen.width <1600)) {
document.write('<link rel="stylesheet" href="fileadmin/template/res/stylesheet1280.css" type="text/css" />');
}
if (screen.width >= 1600) {
document.write('<link rel="stylesheet" href="fileadmin/template/res/stylesheet1600.css" type="text/css" />');
}