var browser = navigator.appName;
var Win, Mac, Other;
  Win = navigator.userAgent.indexOf("Win") > -1;
  Mac = navigator.userAgent.indexOf("Mac") > -1;
  Other = !(Win || Mac);
  
if (browser =="Microsoft Internet Explorer" && Win) {
document.write('<link href="main_style_ie.css" rel="stylesheet" type="text/css">');
} else {
document.write('<link href="main_style.css" rel="stylesheet" type="text/css">');
}