you tube api is this url valid or not - json url in end of html to get feeds

you tube api is this url valid or not - json url in end of html to get feeds

you tube api is this url valid or not - json url in end of html to get
feeds? if is valid if insert in browser address bar must get the feeds ? I
do not get any either in javascript code, anyway is it valid or...?
http://gdata.youtube.com/feeds/users/lynda/uploads?alt=json-in-script&max-results=30&category=Villalobos&callback=listVideos