needed by a particular element type for that element type to function correctly; (2) optional attributes used to modify the default functionality of an element type; (3) standard attributes supported by many element types; and (4) event attributes used to cause element types to specify scripts to be run under specific circumstances.

Doctype HTML is a declaration that tells the browser what version of HTML the document is written in.

Some attribute types function differently when used to modify different element types. For example,

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