firefox does not close window

All the scripts you are trying are meant to close browser without giving confirmation box to user. But this trick works only in IE and not in FireFox hence simply use

Page.ClientScript.RegisterStartupScript(Me.[GetType](), "asr4", "window.close();", True)

This is not even working in chrome

But it works in FireFox and IE

It works in IE but not in firefox and chrome..........check my code below :

 Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        Dim host As System.Net.IPHostEntry

        host = System.Net.Dns.GetHostByAddress(Request.ServerVariables.Item("REMOTE_HOST"))

        strHostName = host.HostName.ToLower()

        strHostIP = System.Net.Dns.GetHostEntry(strHostName).AddressList(0).ToString()

        If Not (strHostName = "ved1" Or strHostName = "amit" Or strHostName = "deepak" Or strHostName = "santos" Or strHostName = "shafeeq1") Then

            'Page.ClientScript.RegisterStartupScript(Me.[GetType](), "asr4", "alert('Dear " + strHostName.ToUpper() + " you dont have permission to access this page');var win=window.open('','_self');win.close();", True)

            Page.ClientScript.RegisterStartupScript(Me.[GetType](), "asr4", "window.close();", True)

            txtedit.Visible = False

            Exit Sub

        End If

First dark/highlighted portion works in Chrome and IE and second one work's only in IE

        user.Text = "Welcome " + strHostName

        user.Visible = True

        If Not IsPostBack Then

            bindgrid()

        End If

    End Sub