As we saw in the last chapter, the element type declaration constrains the element's content. In this chapter we will see how an attribute list declaration constrains the attribute's content.
Attributes provide additional information about elements.
Elements and attributes also exist in HTML . It is, instead, additional data about that particular element. Attributes are created in the DTD, when the elements are specified. They are specified through an attribute list. Attribute declarations identify which elements may have attributes, what types of attributes they may have, what values the attributes may hold, and what default value each attribute has.