abbr elementtitle attribute has special semantics on this element.HTMLElement.The abbr element represents an
  abbreviation or acronym, optionally with its expansion. The title attribute may be
  used to provide an expansion of the abbreviation. The attribute, if
  specified, must contain an expansion of the abbreviation, and
  nothing else.
The paragraph below contains an abbreviation marked up with the
   abbr element. This paragraph defines the term "Web Hypertext Application Technology
   Working Group".
<p>The <dfn id=whatwg><abbr title="Web Hypertext Application Technology Working Group">WHATWG</abbr></dfn> is a loose unofficial collaboration of Web browser manufacturers and interested parties who wish to develop new technologies designed to allow authors to write and deploy Applications over the World Wide Web.</p>
An alternative way to write this would be:
<p>The <dfn id=whatwg>Web Hypertext Application Technology Working Group</dfn> (<abbr title="Web Hypertext Application Technology Working Group">WHATWG</abbr>) is a loose unofficial collaboration of Web browser manufacturers and interested parties who wish to develop new technologies designed to allow authors to write and deploy Applications over the World Wide Web.</p>
This paragraph has two abbreviations. Notice how only one is
   defined; the other, with no expansion associated with it, does not
   use the abbr element.
<p>The <abbr title="Web Hypertext Application Technology Working Group">WHATWG</abbr> started working on HTML5 in 2004.</p>
This paragraph links an abbreviation to its definition.
<p>The <a href="#whatwg"><abbr title="Web Hypertext Application Technology Working Group">WHATWG</abbr></a> community does not have much representation from Asia.</p>
This paragraph marks up an abbreviation without giving an expansion, possibly as a hook to apply styles for abbreviations (e.g. smallcaps).
<p>Philip` and Dashiva both denied that they were going to get the issue counts from past revisions of the specification to backfill the <abbr>WHATWG</abbr> issue graph.</p>
If an abbreviation is pluralized, the expansion's grammatical number (plural vs singular) must match the grammatical number of the contents of the element.
Here the plural is outside the element, so the expansion is in the singular:
<p>Two <abbr title="Working Group">WG</abbr>s worked on this specification: the <abbr>WHATWG</abbr> and the <abbr>HTMLWG</abbr>.</p>
Here the plural is inside the element, so the expansion is in the plural:
<p>Two <abbr title="Working Groups">WGs</abbr> worked on this specification: the <abbr>WHATWG</abbr> and the <abbr>HTMLWG</abbr>.</p>
Abbreviations do not have to be marked up using this element. It is expected to be useful in the following cases:
abbr element with a title attribute is an alternative to
   including the expansion inline (e.g. in parentheses).abbr element with a title attribute or include the expansion
   inline in the text the first time the abbreviation is used.abbr element
   can be used without a title
   attribute.Providing an expansion in a title attribute once will not necessarily
  cause other abbr elements in the same document with the
  same contents but without a title
  attribute to behave as if they had the same expansion. Every
  abbr element is independent.
data elementvalueinterface HTMLDataElement : HTMLElement {
           attribute DOMString value;
};
   The data element represents its
  contents, along with a machine-readable form of those contents in
  the value attribute.
The value
  attribute must be present. Its value must be a representation of the
  element's contents in a machine-readable format.
When the value is date- or time-related, the more
  specific time element can be used instead.
Этот элемент может быть использован для нескольких целей.
When combined with microformats or the microdata attributes defined in this
  specification, the element serves to provide both a machine-readable
  value for the purposes of data processors, and a human-readable value
  for the purposes of rendering in a Web browser. In this case, the
  format to be used in the value
  attribute is determined by the microformats or microdata
  vocabulary in use.
The element can also, however, be used in conjunction with
  scripts in the page, for when a script has a literal value to store
  alongside a human-readable value. In such cases, the format to be
  used depends only on the needs of the script. (The data-* attributes can also be useful in
  such situations.)
The value IDL
  attribute must reflect the content attribute of the
  same name.
Here, a short table has its numeric values encoded using
   data so that a script can provide a sorting mechanism
   on each column, despite the numbers being presented in textual
   form in one column and in a decomposed form in another.
<table class="sortable"> <!-- class used by script to find tables to which to add sorting controls --> <thead> <tr> <th> Game <th> Corporations <th> Map Size <tbody> <tr> <td> 1830 <td> <data value="8">Eight</data> <td> <data value="93">19+74 hexes (93 total)</data> <tr> <td> 1856 <td> <data value="11">Eleven</data> <td> <data value="99">12+87 hexes (99 total)</data> <tr> <td> 1870 <td> <data value="10">Ten</data> <td> <data value="149">4+145 hexes (149 total)</data> </table>