Setting value in html control in code behind without making server control

 <input type="text" name="txt" />
    <%--Pleas note I don't want put runat=server here to get the control in code behind--%>
    <asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click" />

Code behind

protected void Page_Load(object sender, EventArgs e)
{
    if (!Page.IsPostBack)
    {
        //If I want to initlize some value in input, how can I set here
    }
}
protected void Button1_Click(object sender, EventArgs e)
{
    Request["txt"] // Here I am getting the value of input
}

Thanks