--- C# ---
string vBrowser = System.Web.HttpContext.Current.Request.Browser.Browser.ToLower();
// or string vBrowser = Request.Browser.Browser.ToLower(); //for local page
switch (vBrowser)
{
case "firefox":
do something ...
break;
case "ie":
do something ...
break;
case "safari":
do something ...
break;
default:
do something ...
break;
}