javascript:void(0)的用途
点击一个链接点击后,页面上不做任何事情,多用于绑定响应事件 如:通过js代码,为其绑定’submit(提交表单事件)’
而且,往往不定义该代码,还可能完成不了所绑定的’submit’事件.

参考:https://zhidao.baidu.com/question/2202019854738731028.html

示例代码:

  <script>

    window.onload=function (ev) {

        function sub(){

            alert("表单被提交了");
            var formObj = document.getElementById("form").submit;



        }

        document.getElementById("delselect").onclick=function (ev1) {

        var checkedNum = document.getElementsByName("userid");
        var checkedBoolean = false;
            for (var i = 0;i<checkedNum.length;i++){

             if (checkedNum[i].checked) {//判断多选框是否被选中
                 sub();
                 break;


             }

         }


        }

    }


    </script>
    
    <form id="form" action="${pageContext.request.contextPath}/DeleteUserServlet" method="post">
        ${pageContext.request.contextPath}
    <table border="1" class="table table-bordered table-hover">
        <tr class="success">
            <th><input type="checkbox"></th>
            <th>编号</th>
            <th>姓名</th>
            <th>性别</th>
            <th>年龄</th>
            <th>籍贯</th>
            <th>QQ</th>
            <th>邮箱</th>
            <th>操作</th>
        </tr>


        <c:forEach items="${list}" var="paraminfo" varStatus="num" >
        <tr>
            <th><input type="checkbox" name="userid" value="${paraminfo.id}"></th>
                <td>${num.count}</td><!-- 编号 根据num数值获取 -->
                <td>${paraminfo.name}</td>
                <td>${paraminfo.gender}</td>
                <td>${paraminfo.age}</td>
                <td>${paraminfo.address}</td>
                <td>${paraminfo.qq}</td>
                <td>${paraminfo.email}</td>
                <td><a class="btn btn-default btn-sm" href="${pageContext.request.contextPath}/findUserServlet?userid=${num.count}">修改</a>&nbsp;<a class="btn btn-default btn-sm" href="">删除</a></td>
        </tr>
        </c:forEach>

    </table>
    </form>