You do not have to download the file before you play it. Windows Media is another format for audio and video files. There is a Mac version available. PDF files are used to to make precisely-formatted documents available via the web. Documents using the PDF format can only be viewed with the Adobe Acrobat Reader software.
Cookies are small text files used to record information about a web site visitor.
The site creates the cookie on the visitor's computer and then uses it to identify the visitor each time the site is accessed. ABC sites only use cookies to identify participants in online forums. They are not used to record any other information. JavaScript adds extra functions to web pages. Examples include small pop-up windows and images that change when you pass a mouse pointer over them.