Are you the one writing the code for your site? Do you know about socket.io?
Here is info for the Gox api:
https://en.bitcoin.it/wiki/MtGox/APIYou could also modify slush' sierrachart bridge to gather the data and put it into a file format you can use. The default used is .scid which would be useless without sierrachart software, but you could rewrite it to use a more common extension like .csv which would be easily implemented.