AJAX :: Display Data Row By Row

I have a script that uses ajax and php to search a database and show the results. What it is doing at the moment is it takes the user input from the search form, and then send that to php page via ajax, and what ever PHP page returns it just show that at once, for example, if php returns 20 rows, it will show them all at once. What i want is that it will show row by row instead of at once. Like it search and then display row 1, then 2 then 3 then 4 so on till the end. So i dont want all the search to be displayed at once.