I always recommend using a library like jQuery to do Ajax -- there are just too many nuances and browser dependencies to bother doing Ajax "by hand".
The fact that you are updating a table isn't an issue. You can either use a jQuery call such as $.getJSON() to get the data from the server necessary to repopulate the table, or you could just use .load() and return the pre-formatted table (easy with
JSP or php) to replace the whole thing.