Here is a list of those collections that are available. In each case the collection is an array of the particular objects within the page that can either be accessed by number (with the entries being accessed in the order that they appear in the web page) or by name (if the objects have a name or id attribute that allocates them a name).
Probably the most useful of these collections are forms, images, and links (in that order). As there is usually only one form in a page document.forms provides access to all of the fields within that form. Similarly the images and links collections provide easy access to interact with all of the images and links on the web page.
Of course these collections only give access to a small part of the page content. The standard document object model is slightly more complicated to code than these simple collection references but it provides access to every single part of the page (both HTML and stylesheets). We'll look at that in the following tutorials.