Changes in HTML 5 - <button> Tag

What's new in HTML 5

A new set of attributes have been added which can be used to override various attributes on the <form> tag.

<button> attributeoverrides <form>
formactionaction
formenctypeenctype
formmethodmethod
formnovalidatenovalidate
formtargettarget

In addition, the autofocus="autofocus" and form attributes have been added.

Differences between HTML 5 and earlier versions of HTML

The 2000-2010 Recommendations from the W3C HTML Working Group defined the HTML namespace for the button element type name along with the names of all HTML element types. In older (pre-2000) versions of HTML, element type names were not associated with a namespace.