Print specific columns of GridView in ASP.Net

 hi

i am printing the gridview in below code.. now i want to print the required colunm in the gridview.. by using below code its display all gridview column. but i need to print only first 5 column 1ly. 

<asp:Button ID="btnprt" runat="server" OnClientClick="PrintGridData()" CssClass="prt prt_btn prt_large" Text="PRINT" />

<script type="text/javascript">
        function PrintGridData() {
            var prtGrid = document.getElementById('<%=GridView1.ClientID %>');            
    prtGrid.border = 0;
    var prtwin = window.open('', 'PrintGridViewData', 'left=100,top=100,width=1000,height=1000,tollbar=0,scrollbars=1,status=0,resizable=1');
    prtwin.document.write(prtGrid.outerHTML);
    prtwin.document.close();
    prtwin.focus();
    prtwin.print();
    prtwin.close();
}
</script>