var browserName=navigator.appName;
if (browserName=="Microsoft Internet Explorer")
{
//load ie friendly stylesheet
//document.write('')
}
else
{
if ((parseFloat(navigator.appVersion)) >= 5 )
{
// if ns version is great than or equal to 5 (6) load this stylesheet
// document.write('')
} else {
//if you have a really ancient browser ;-) (ie. NS 4.7 or earlier) load this stylesheet
//document.write('')
}
}