选中复选框后禁用复选框

我正在使用JSF和Javascript

复选框

<h:selectBooleanCheckbox onclick="handlePaymentButtons()" 
class="chkBox"></h:selectBooleanCheckbox>Yes I agree terms and Conditions

<script>
            function handlePaymentButtons(){
                console.log("we are here..");

                var box = document.getElementsByClassName("chkBox");
                box.disabled =true;
                console.log(box);
                gButton.enable();

            }
        </script>

我只想禁用当前选中的复选框。