autocomplete [HTML5]

This attribute indicates whether the value of the control can be automatically completed by the browser. Possible values are:
  off: The user must explicitly enter a value into this field for every use, or the document provides its own auto-completion method; the browser does not automatically complete the entry.
  on: The browser can automatically complete the value based on values that the user has entered during previous uses.

If the autocomplete attribute is not specified on an textarea element, then the browser uses the autocomplete attribute value of the <textarea> element's form owner. The form owner is either the form element that this <textarea> element is a descendant of or the form element whose id is specified by the form attribute of the input element. For more information, see the autocomplete attribute in <form>.