问题
In some texts about XML, the terms tag and element seem to be used interchangeably. Do they mean the same thing, or are do these terms represent different things?
回答1:
Tags mark the start and end of an element.
<foo>— start tag</foo>— end tag<foo></foo>— element
See the specification:
Each XML document contains one or more elements, the boundaries of which are either delimited by start-tags and end-tags, or, for empty elements, by an empty-element tag.
See also section 5 of NOT the comp.text.sgml FAQ
来源：https://stackoverflow.com/questions/12027770/what-is-the-difference-between-a-tag-and-an-element