if (screen.width <= 800) {
  document.write('<link href="mystyle/wngh800.css" rel="stylesheet" type="text/css">');
}
else if (screen.width <=1024) {
	document.write('<link href="mystyle/wngh1024.css" rel="stylesheet" type="text/css">');
}
else if (screen.width <=1280) {
	document.write('<link href="mystyle/wngh1280.css" rel="stylesheet" type="text/css">');
}
else if (screen.width >1280) {
	document.write('<link href="mystyle/wngh1280.css" rel="stylesheet" type="text/css">');
}