要将新行插入表中的某个索引处，请使用jQueryval()和insertBefore()方法。您可以尝试运行以下代码以了解如何在表中插入新行-
<html>
<head>
<title>jQuery Example</title>
<script src = "https://cdn.staticfile.org/jquery/3.2.1/jquery.min.js"></script>
<script>
$(document).ready(function(){
$('#index').val($('#myTable tbody tr').length);
$('#btn1').click(function(){
var indx = $('#index').val()-1;
var newRow = $('<tr><td>New row is added at index '+$('#myTable tbody tr').length+'</td></tr>');
newRow.insertBefore($('#myTable tbody tr:nth('+indx+')'));
});
});
</script>
</head>
<body>
<table id="myTable">
<tbody>
<tr>
<td>This is row 1</td>
</tr>
<tr>
<td>This is row 2</td>
</tr>
</tbody>
</table>
<input id="index"/>
<button type="button" id="btn1">Add</button>
</body>
</html>