Redirecting to previous page by avoiding required field validation

i have 3 pages

1. Login


2. Home


3. Add employee
   
   Now i've a back button in "Add Employee" page which should redirect to the previous page! but when i click on it the required field validators will turn on!! how can i avoid that for back button?
   
   I tried using two types of code but both gets stuck in there for validation.
   

---

protected void Button2_Click(object sender, System.EventArgs e)
{
     string prevPage = Request.UrlReferrer.ToString();
     Response.Redirect(prevPage);
}

And this

protected void Button2_Click(object sender, EventArgs e)
    {
        Response.Redirect("home.aspx");
    }