This call works one of 2 ways. If you have provided a valid user_id and a user_name the API will open the user page for the user you specified (User info can be pulled from features like high scores and save data).
import com.newgrounds.API; var loaded:Boolean = API.loadUserPage(user_id:Number, user_name:String);
If no paramenetsr are passed, the local user is playing from a site with NewgroundsAPI integration and they have a valid user session, this will open their user page in a new browser window.
If no user page is loaded, this call will return false.