Avoid page load on click of a button

If Not Page.IsPostBack Then
                btnAddSub.Visible = False
               
            End If

In this case you need to use jquery/Javascript.Without javascript whenever you click on your button PageLoad will be Fired.

another scenario is if you don't have any code written on the PageLoad then Set the AutoEventWireup="False" in page directive of .aspx page.By setting this property this function will not be called.

Already I have a piece of code in

If Not Page.IsPostBack Then
                btnAddSub.Visible = False
                btnExportToExcel.Visible = False
                btnExtract.Visible = True
                gvBVALPrices.Visible = False
            End If

On the click event of the button , i have the following code which shows the check box.

Protected Sub btnAddSub_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnAddSub.Click

        dv.Visible = True

        chkColumns.Items.Clear()
        Dim count As Integer = gvBVALPrices.Columns.Count
        Dim i As Integer
        For i = 0 To count - 1
            chkColumns.Items.Add(gvBVALPrices.Columns(i).ToString)
        Next
        chkColumns.Items(0).Selected = True
        chkColumns.Items(1).Selected = True
        chkColumns.Items(2).Selected = True
        chkColumns.Items(3).Selected = True
        chkColumns.Items(4).Selected = True
        chkColumns.Items(5).Selected = True

    End Sub

So please provide me a jquery to prevent the page load on the button click event.