DTD Entities

From http://www.w3schools.com (Copyright Refsnes Data)

# DTD - Entities

Entities are variables used to define shortcuts to standard text or special characters.

- Entity references are references to entities

- Entities can be declared internal or external

## An Internal Entity Declaration

### Syntax

    <!ENTITY entity-name "entity-value">

### Example

    DTD Example:

    <!ENTITY writer "Donald Duck.">
    <!ENTITY copyright "Copyright W3Schools.">

    XML example:

    <author>&writer;&copyright;</author>

Note: An entity has three parts: an ampersand (&), an entity name, and a semicolon (;).

## An External Entity Declaration

### Syntax

    <!ENTITY entity-name SYSTEM "URI/URL">

### Example

    DTD Example:

    <!ENTITY writer SYSTEM "http://www.w3schools.com/entities.dtd">
    <!ENTITY copyright SYSTEM "http://www.w3schools.com/entities.dtd">

    XML example:

    <author>&writer;&copyright;</author>

From http://www.w3schools.com (Copyright Refsnes Data)