SOURCE

$(function(){
 $('input:button').click(function(){
     let name=$("input:eq(0)").val()
     let cls=$("input:eq(1)").val()
     let score=$("input:eq(2)").val()
     let node=$('<tr><td>'+g()+'</td><td>'+name+'</td><td>'+cls+'</td><td>'+score+
    '</td><td><a href="#" onclick="del(this)">删除</a></td></tr>"')
    $('tbody').append(node)
 })
})
function next_id(){
    var current_id=0;
    return function(){
        return ++current_id;
    }
}
var g=next_id();
for(let i=0;i<0;i++){
    console.log(g())
}
function del(obj) {
    var tr = obj.parentNode.parentNode;
    if (tr != null) {
        tr.parentNode.removeChild(tr)
    }
}

<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<form> 
     <input placeholder="姓名"/>
     <input placeholder="班级"/>
     <input placeholder="成绩"/>
    <input  type="button" value="添加"/>
</form>
<table border="=1" cellspacing=0 cellspadding=5>
    <thead>
        <tr>
            <th>编号</th>  
            <th>姓名</th>
            <th>班级</th>
            <th>成绩</th>
            <th>操作</th>
        </tr>
    </thead>
    <tbody>
        
    </tbody>
</table>