if (navigator.appName == "Opera") { 
document.write('<link href="styles/styles_ff.css" rel="stylesheet" type="text/css">')
}
else if (navigator.appName == "Netscape") { 
document.write('<link href="styles/styles_ff.css" rel="stylesheet" type="text/css">')
} 
else {
document.write('<link href="styles/styles_ie.css" rel="stylesheet" type="text/css">')
}