How to apply javascript for collapsable gridview child

http://www.aspforums.net/Threads/172293/Collapsable-Gridview-with-parent-and-child-gridview/

I have written a script to check all check boxes in a grid view, I would like to apply this script for child grid view grdchild how can i add this script 

  <script type="text/javascript">

        function checkAllBoxes() {

            //get total number of rows in the gridview and do whatever
            //you want with it..just grabbing it just cause
            var totalChkBoxes = parseInt('<%= this.grdchild.Rows.Count %>');
            var gvControl = document.getElementById('<%= this.grdchild.ClientID %>');

            //this is the checkbox in the item template...this has to be the same name as the ID of it
            var gvChkBoxControl = "chkBoxChild";

            //this is the checkbox in the header template
            var mainChkBox = document.getElementById("chkBoxAll");

            //get an array of input types in the gridview
            var inputTypes = gvControl.getElementsByTagName("input");

            for (var i = 0; i < inputTypes.length; i++) {
                //if the input type is a checkbox and the id of it is what we set above
                //then check or uncheck according to the main checkbox in the header template             
                if (inputTypes[i].type == 'checkbox' && inputTypes[i].id.indexOf(gvChkBoxControl, 0) >= 0)
                    inputTypes[i].checked = mainChkBox.checked;
            }
        }
    </script>