Validate check boxex in gridview with confirmation

    <script language="javascript" type="text/javascript">
        function validateChkBox() {
          var isValid = false;
            var gridView = document.getElementById('ctl00_ContentPlaceHolder111_grd_ctl00');

            for (var i = 1; i < gridView.rows.length; i++) {
                var inputs = gridView.rows[i].getElementsByTagName('input');
                if (inputs != null) {
                    if (inputs[0].type == "checkbox") {
                        if (inputs[0].checked) {
                            isValid = true;
                            return confirm('You are about to delete the user.  Are you sure you wish to continue?')

                        }
                    }
                }
            }
            alert("Please select at least one checkbox");
            return false;
        }

    </script>