There may well be parts of this document which "don't look right" given the exact browser/machine/fonts combination. Consider this to to a personal example of the problem of using mathemathics in HTML documents, all the examples below function in the authors environment.
Mathematical typesetting within WWW dosuments using HTML has always
been problematic. HTML as a page description/layout description was
designed using a minimal client/browser model, that is, the content
needed to be reliably displayed on all platforms no matter how primitive.
Indeed, it wasn't even assumed that the browser would have graphical
capabilities (eg: lynx) and it was recommended that authors of HTML
files which included graphics would include the "alt" tag with images
so that non image capable browsers would have some idea what the image
It was also assumed that the HTML document would not be able to make assumtions regarding fonts, most browsers give control over fonts to the user not the author. One immediate issue this raises is the inability for authors to use typefaces consisting of Greek symbols, a common convention in scientific documentation.
The remainder of this document will discuss some of the solutions to the problem of delivering mathematical typsetting within HTML files. The examples shown here should display correctly on the major WWW browsers, they have been designed however using NetScape version 3.
While this technique works well for equations on a line by themselves,
it can look ugly when an attempt is made to include images on a line with
other text. The typeface is normally different, has a different size, and
the images will not normally align vertically with the text.
There is an align middle tag for the <img> tag which can be used to align the symbols closer to the right line height, see for example the following 4 lower case greek characters: pi (), beta (), lower case x (), phi ().
The whole alphabet based on the standard "Symbol" font is
Some extensions to HTML allow font specification, this will not be discussed here as it obviously depends on the character sets available on the clients computer. For normal text if the viewer sees a different font from the one specified they can at least still read it. If the font was used because it contains special symbols then the viewer cannot in general determine any meaning if the result is displayed in another font.
While the exact implementation of these is browser specific, they normally automatically reduce the font size of the subscript and superscript. Unfortunately they don't work ideally in combination Pij2, that is, the ij doesn't appear directly below the 2.
The Greek character set images used above can also have superscripts
and subscripts added to them although they can't be the superscript
of superscript themselves, for example,
This can be extended to other commonly used symbols such as integrals () and square roots ()
01 f(x) dx = 2
x y z - + - + - = 1 a b cUnfortunately not all browsers allow you to include other HTML styles within <pre> </pre>, NetScape does so the following will work
x2 y2 z2 - + - + - = r2 a2 b2 c2In general this technique should be avoided, not only isn't it very attractive but it does make assumptions of the font size when applying other HTML formatting such as bold, italic, etc.
|Column 1||Column 2||Column 3||Column 4||Column 5|
Tables can be used to lay out multiple items, an obvious application is to place labels on the right for equations, the line below consists of a two column, one row table. The first cell holds the equation and the second the right aligned equation number.
|. . . . (3a)|
A table without borders is suitable for items in regular rows and columns
Each of the above items including the individual signs are in their own table row/column.