HTML Topics: Symbols

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Symbols

Given that the Web was invented by scientists at Cern in Switzerland, it may seem surprising at first that little thought was given to the problem of displaying Greek letters and mathematical symbols in Web documents. The early method for the display of Greek characters in HTML documents involved the use of the symbol font available on most computers. Unfortunately, the latest browsers removed backwards compatibility (a retrograde step) with this de facto use of the symbol font, and so a move to new standards has been enforced.

The new method involves the use of character names or encoding number. These are always preceded by the ampersand character (&) and followed by a semicolon (;). Referencing by what is known as their Unicode encoding number takes the form &#nnn; or &#nnnn; where nnn or nnnn is a three or four digit decimal number, respectively.

The Greek letter alpha using character names is α

The Greek letter alpha using encoding number is α

Greek Letters

If you do not see Greek letters in the table, then your system is not correctly configured to view them or you are using an out-of-date web browser (see the technical specification web page provided with the course details).

Mathematical Characters

In addition to the Greek characters, the physical sciences also make use of various mathematical characters. A table of some of the more common ones is given below. They have a similar syntax to those above.

Accented Characters

Finally, there are a number of other characters that you will also need. Accented characters are common to many of the western European languages, and these can be referenced using a similar syntax to the above, i.e. &Character_Name;. Thus, the entity Å produces the symbol Å for Ångström (which is the SI derived unit commonly used by nearly all crystallographers for the units of bond length), while the ö in Ångström is produced by ö.

If you need to check the full list of names, refer to the list of HTML character codes given in the Web Authoring Links.

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