HTML attributes are modifiers of HTML elements. They generally appear as name-value pairs, separated by "=", and are written within the start tag of an element, after the element's name: <''tag'' ''attribute''="''value''">(content to be modified by the tag) Where tag names the HTML element, attribute is the name of the attribute, set to the provided value. The value may be enclosed in single or double quotes, although values consisting of certain characters can be left unquoted in HTML (but not XHTML). Leaving attribute values unquoted is considered unsafe.