javascript store of db values

I have seen this done but not sure how to go about it. Go to the DB and get values and store them in a javascript hash for much quicker lookup. I have a drop down with a few items and I display the "long" name version next to the drop down would much rather get the values out of a JS hash than going to the server every time. Is there a way to dot that or someway similar for not a lot of data to reference for quicker lookup and also not having to go to the server every time for it? The data is has a 'name' and also a 'long_name' in the db.