javascript Alert message

protected void Button1_Click(object sender, EventArgs e)
    {
        if ((DropDownList1.SelectedItem.Text == "---- Select ----") || (TextBox1.Text == "") || (TextBox2.Text == ""))
        {
            Label1.Visible = true;
            Label1.Text = "All fields are mandatory, can not left blank.";
            TextBox1.Text = "";
            TextBox2.Text = "";
        }
        else if ((TextBox1.Text != TextBox2.Text))
        {
            Label1.Visible = true;
            Label1.Text = "Confirm Password does not match, Try Again.";
            TextBox1.Text = "";
            TextBox2.Text = "";
            TextBox1.Focus();
        }
        else
        {
            string lsUsrName, lsPwd;
            lsUsrName = DropDownList1.SelectedItem.Text;
            lsPwd = TextBox1.Text;

            Response.Write("<script>var resp = window.confirm ('Are you sure want to change password?');alert(resp);</script>");

        }
    }