That means that the code on this page:
Code:
http://awebsite.com/anotherwebsite/wp-admin/admin-ajax.php
should do the limiting.
Possibly you could pass another parameter specifying how many reviews you want and then the PHP code can limit them. If the PHP code is pulling the reviews from a database, then the PHP code would simply pass the limit along to the SQL query that gets the data.
Example:
Code:
http://awebsite.com/anotherwebsite/wp-admin/admin-ajax.php?action=repagent_reviews_js&id=1182&count=5