How to store youtube gdata api results using json-in-script & json?

Question

In the following link http://code.google.com/apis/gdata/docs/json.html#Request

1. its given how to get the response results for json-in-script. But how to do I append the result if i want to call http://gdata.youtube.com/feeds/api/videos?q=userSearchTerm&start-index=1&max-results=50&alt=json-in-script&callback=myFunction multiple times as i want to have more than 50 video results.

2. How do i get response from http://gdata.youtube.com/feeds/api/videos?q=userSearchTerm&alt=json&start-index=1&&max-results=50 to send it to eval()

var myObj = eval( '(' + JSON_response + ')' );

how does JSON_response exactly look like?

please help, im a beginner for this area.

thanks in adv srini