THE BASEFONT TAG

from John Gleason's HTML tutorials, with grateful acknowlegement

The BASEFONT tag changes the size of ALL the body text after the BASEFONT tag except for HEADERS (defined by H1, H2, H3, H4, H5 and H6). Thus the BASEFONT tag is used to suggest a default font size. Here is the statement that changes the default size to 5:
<BASEFONT SIZE="5">

Note the following discussion points:

BASEFONT is one word (no spaces). Most browsers now recognize the BASEFONT tag.
The SIZE attribute is an integer value ranging from 1 to 7. The default value is "3" which is the font size the browser normally displays. Thus SIZE="5" is considered to be 2 sizes (also called 2 levels or 2 steps) larger than the default size of 3. Since the actual size of text varies from browser to browser, it is impossible to define exactly how big one size is. We only know that SIZE="5", for example, is 2 sizes larger than the normal default size of 3.
Relative font sizes also work with the BASEFONT tag. To indicate a relative base font size, use the "+" or "-" with the number value. You can denote a relative base font size from +1 to +7 and from -1 to -7.
For example, while <BASEFONT SIZE="5"> would set the default base font size to "5",

<BASEFONT SIZE="+5">

would set the new default base font size 5 levels larger than the current base font size. A "relative" size is always given "relative" to the current default size. Thus while <BASEFONT SIZE="2"> gives a default base font of size "2",

<BASEFONT SIZE="-2">

would give a base font size 2 levels smaller than the default size and

<BASEFONT SIZE="+2">

would give a base font size 2 levels larger than the default size.

The BASEFONT tag is not a container element. That is, there is no closing BASEFONT tag.
BASEFONT applies to all normal and preformatted tags but not to headers. Be aware then, that using a BASEFONT tag could make the body text larger than the headers which could confuse your readers.
You cannot use BASEFONT to change the size of individual characters or of a block of text. There are other tags such as FONT, BIG and SMALL (also described in this lesson) that can be used for this purpose.
Use only one BASEFONT tag in each HTML document as the BASEFONT tag affects all the succeeding text. Normally the BASEFONT tag is used to change the base font of the entire page and if this is the case, the BASEFONT tag should then be placed right after the opening BODY tag. Thus you would have the HEAD, TITLE and BODY tags followed by the BASEFONT tag.
Choosing a large base font size may not look good in some browsers. However, you can use the BASEFONT tag to increase the size of your text in short web pages to give a little more importance to the whole page. Conversely, you can use a smaller base font in lengthy text intensive pages to fit more text on a page.
In general you should have a good reason to change the base font size of your text. Users may already have specified in their browser settings how they prefer to view text.