Explain Browser back button disable

hi to all

i got the code for browser back button disable.the code is below
HttpContext.Current.Response.Buffer = true;
HttpContext.Current.Response.ExpiresAbsolute = DateTime.Now.AddDays(-1d);
HttpContext.Current.Response.Expires = 0;
HttpContext.Current.Response.CacheControl = "no-cache";

please explain this code. this code will protect the css and js files. how work properly css and js files. please anyone explain this code.

b ...