var ua = navigator.userAgent;
if(ua.indexOf("MSIE 5") != -1){
if(ua.indexOf("Mac") != -1){
document.write('<link rel="stylesheet" type="text/css" media="all" href="./style/intro_mac_ie.css" />');
}
if(ua.indexOf("Win") != -1){
document.write('<link rel="stylesheet" type="text/css" media="all" href="./style/intro_win_ie.css" />');
}
}
if(ua.indexOf("MSIE 6") != -1){
document.write('<link rel="stylesheet" type="text/css" media="all" href="./style/intro_ie6.css" />');
}