Similarly, HTML files instruct the browser where to find sounds, quicklime moves, RealAudio files, etc. Sounds, movies, Flash animation, and other media do not exist within the HTML document. HTML files are text, only text. Almost all HTML tags are made up of open and close components. You can write HTML tags as either lowercase or uppercase.
Syntax is, however, important and in some cases, for some browsers, crucial.
There are cases when an attribute must be enclosed in quotes for instance. We'll learn about these as they arise. HTML defaults and attributes Many HTML tags can have attributes that modify the functions, options or features of the tag. The corollary is that tags that can have attributes have defaults. Physical tags describe a document's layout .