var uAnt = navigator.userAgent;
var os = "win"; //下記判定時以外のOS

if (uAnt.indexOf("Win") != -1) os = "win";
if (uAnt.indexOf("Mac") != -1) os = "mac";

if (os =="win"){
	var brw = "ie"; //WIN用下記判定時以外のブラウザ
}else{
	var brw = "ie"; //MAC用下記判定時以外のブラウザ
}

if (uAnt.indexOf("Opera") > -1){
	brw = "ie";
}else if (uAnt.indexOf("MSIE") > -1){
	brw = "ie";
}else if (uAnt.indexOf("Safari") > -1){
	brw = "ie";
}else if (uAnt.indexOf("Firefox") > -1){
	brw = "ie";
}else if (document.layers){
	brw = "ie";
}else if (uAnt.indexOf("Netscape6") > -1){
	brw = "nn6";
}else if (uAnt.indexOf("Netscape/7") > -1){
	brw = "ie";
}

document.write('<LINK REL="stylesheet" TYPE="text/css" HREF="/css/'+os+'_'+brw+'.css">');