An HTML document is an ASCII text file. This file contains instructions, which are called tags, to the browser (e.g. Internet Explorer, Netscape Navigator, Voyager) to tell it how to display the text and images that we want to appear on-screen.
Tags are ALWAYS enclosed by the less-than (<) and the more-than (>) signs.
There are certain characters that, because they are used in the coding, cannot simply be typed into your document. There is an exhaustive list of these characters, some of which are in the chapter on Special Characters. The less-than and more-than signs are included amongst these, so the code that I actually typed to show the above was.....
Tags are ALWAYS enclosed by the less-than (<) and the more-than (>) signs.
However, the ampersand sign (&) is also one of these, so to show you what I had first typed, I then had to type something even further different! All will be revealed as you progress through this tutorial.
There are many of these tags and they are the key to how HTML operates. Usually they appear in pairs (of course, there have to be some exceptions) where the second tag is identical to the first but prefixed with a forward slash thus .....
<TAG> .......... </TAG>
One important thing to bear in mind is that all tags use American English for their spelling so, for example, centre is <CENTER>, colour is <COLOR> and etc.
Tags are not case sensitive! Whether you write them in upper or lower case is entirely down to your own preference. Personally, I prefer them to be lower case but for the clarity of the examples shown in this tutorial I shall use upper case when writing on-screen the command(s) in use, although the actual commands used (which you do not see) will be in lower case.
All files have to to be saved with a suffix of either ".html" or "htm". The latter was introduced as early Microsoft file extensions longer than three characters were not allowed ( Windows 98 corrected that situation) but to do the job properly all files should be saved as ".html" if you can.