在可排序的AJAX上更改表行值

I have a table (Generated with PHP) with Jquery's sortable function and when a table row has been moved into another table, the numbers just in front of the plus icons will be changed (A ajax call to a php script which reorders the numbers and sorts them), although I have to refresh the page to make it visible to the user.

So for example, if row with the number "2.1" gets moved to to the top of the whole table, it should be changed to "1.1" and the ones below should also be changed to 1.2 and so on.

After the ajax call, what can I call to update all the table rows in the middle with the "X.X" numbers?

Each td have a unique ID, example of the td is:

<a class="viewModal sortable" href="" id="10" data-toggle="modal">
  2.1
</a>

Else it would work to reload the whole table although it's only the row in the middle that needs to be updated when a user sorts the rows or adds new links to the row.

Below is the table: