var mybrowser = navigator.userAgent; 
if(mybrowser.indexOf('Safari') != -1) {document.write('<link href="css/safari.css" rel="stylesheet" type="text/css" />'); 

}else if(mybrowser.indexOf('Firefox') != -1 ) {
document.write('<link href="css/firefox.css" rel="stylesheet" type="text/css" />');
}

else if(mybrowser.indexOf('MSIE') != -1 ) {
document.write('<link href="css/ie.css" rel="stylesheet" type="text/css" />');
}

else if(mybrowser.indexOf('Opera') != -1 ) {
document.write('<link href="css/safari.css" rel="stylesheet" type="text/css" />');
}

else {
	document.write('<link href="firefox.css" rel="stylesheet" type="text/css" />');
}