สอบถามการสร้าง function javascript ในไฟล์ .js ใน vs(c#.net) นะค่ะ

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

public partial class Attribute : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        //*** Label ***'
        {
            this.lblText.Attributes.Add("OnClick", "alert('Sawatdee');");
            this.lblText.Style.Add("cursor", "hand");
        }

        //*** Hyperlink ***'
        {
            this.hplText.NavigateUrl = "#";
            this.hplText.Attributes.Add("OnClick", "fncTest();");
        }

        //*** Button ***'
        {
            this.btnSubmit.Attributes.Add("Onclick", "return confirm('Do you want to...?');");
            this.btnSubmit.Style.Add("cursor", "hand");
        }
    }
}