The <closer> element serves the same kind of function as <opener>, but at the end of a <div> rather than at the beginning. It groups together the elements which typically fall at the end of a textual division (especially letters), such as signatures, salutes, and dates. The significant elements it may contain are:
The WWP always uses <closer> when one or more of these elements is present.
Closers and trailers are fairly close in function, but not identical. The WWP defines the differences as follows:
<closer> is for things which are part of the form of the thing whose end is being marked: for instance, the closing salutation of a letter, the date or signature at the end of a poem.
By contrast, a <trailer> marks the end of the division itself--it is not part of the content of the section or division, but is rather part of its enclosure. Things which are typically encoded within <trailer> include words like “Finis” or “The End”, or any other statement of conclusion which appears at the end of a division, such as “Here ends the first Chapter” or “That’s all, folks”. Much less frequent, but illustrative: the word “Unfinished” following the end of an unfinished poem.