<script type="text/javascript">
        function checkAll() {
            var inputs = document.forms[0].elements;
            for (var i = 0; i < inputs.length; i++) {
                if (inputs[i].type == ‘checkbox‘) {
                    if (inputs[i].disabled != true) {
                        if (inputs[i].checked == true) {
                            inputs[i].checked = false;
                        }
                        else {
                            inputs[i].checked = true;
                        }
                    }
                    else {
                        inputs[i].checked = false;
                    }
                }
            }
        }
    </script>