Call popup with passing parameter without page refresh

Hi Dear all expertise,
I am using VS 2005 (asp.net 2.0).
Currently i am facing a problem everytime onclick button call the popup it will refresh the page.
Below is my code, Any suggestion or better idea can do it without refresh

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Dim sParam(1) As String sParam(0) = Me.txtCustName.ClientID sParam(1) = "name" 'Register the js action into image button imgSearchCustomer.Attributes.Add("onclick", JScriptUtil.OpenListPopUpWin(JScriptUtil.PP_Customer, sParam, "720", "500", False)) End Sub


Regards,
Dylan

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