I use 2010 and FireFox browser.
It is OK.
<%@ Page Title="Home Page" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true"
CodeFile="Default.aspx.cs" Inherits="_Default" %>
<asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent">
<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">
Welcome to ASP.NET!
To learn more about ASP.NET visit www.asp.net.
<asp:HyperLink ID="HyperLink1" runat="server" NavigateUrl="~/PDF/test.pdf">HyperLink
You can also find
title="MSDN ASP.NET Docs">documentation on ASP.NET at MSDN.
That is the another link of button click.
http://www.c-sharpcorner.com/UploadFile/5089e0/how-to-open-pdf-files-in-web-brower-using-Asp-Net/