Special Characters and Entities
Consider the mathematical formula that x < y. It is a challenge to represent this in (X)HTML because the browser will automatically assume that < is the opening of a tag. In most cases, the browser, not recognising an element called <y> will simply ignore this "ghost" tag and not print anything. Not what you want.
To get around this problem, it is necessary to replace < with an entity, a code which tells the browser to display <. The code for a less than sign is <. Note the format. The entity begins with an ampersand, is followed by a name ("lt" for "less than"), and completed by a semicolon. You will not be surprised to find that the entity for > (greater than) is >.
Since entities begin with ampersands, you run into the same problem representing this & that as you did representing x < y. In order to actually display an ampersand, you must use the entity &.
We have already seen that typing "word 1 word2" in (X)HTML will produce the text "word 1 word 2". In order to force the browser to display multiple spaces, we must use the non-breaking space entity . The code to produce the large gap between the words would be
word 1 word 2
Note that should not be used for indenting text. Use CSS for this purpose.
Entities may be references by their name, as above, or by numeric codes (preceded by #). The name-code equivalencies of each of entities we have looked at so far are listed below.
| Result | Description | Entity Name | Entity Number |
|---|---|---|---|
| non-breaking space | |   | |
| < | less than | < | < |
| > | greater than | > | > |
| & | ampersand | & | & |
Entities can also be used to represent special characters such as accented letters like é. A large number of entities is available for this purpose. A good list of these entities is available at http://www.degraeve.com/reference/specialcharacters.php.
For convenience, this tutorial will list only those special characters commonly used to represent Old English.
| Result | Description | Entity Name | Entity Number |
|---|---|---|---|
| æ | æsc | æ | æ |
| Æ | capital æsc | Æ | Æ |
| þ | thorn | þ | þ |
| Þ | capital thorn | Þ | Þ |
| ð | eth | ð | ð |
| Ð | capital eth | Ð | Ð |
Note that entity names are case sensitive: æ is not the same as &AELIG;.