document.write('<link rel="stylesheet" href="/'); 
    var agt=navigator.userAgent.toLowerCase(); 
    if (agt.indexOf('chrome') != -1) document.write('style1.css'); 
    else if (agt.indexOf('safari') != -1) document.write('style1.css'); 
    else if (agt.indexOf('msie') != -1) document.write('style.css'); 
    else document.write('style1.css'); 
    document.write('" type="text/css">');