blockquote elementciteinterface HTMLQuoteElement : HTMLElement {
           attribute DOMString cite;
};
    The HTMLQuoteElement interface is
    also used by the q element.
The blockquote element represents a
  section that is quoted from another source.
Content inside a blockquote must be quoted from
  another source, whose address, if it has one, may be cited in the
  cite
  attribute.
If the cite attribute
  is present, it must be a valid URL potentially surrounded by
  spaces. To obtain the corresponding
  citation link, the value of the attribute must be resolved relative to the element. User
  agents should allow users to follow such citation links.
The content of a blockquote may be abbreviated or
  may have context added in the conventional manner for the text's
  language.
For example, in English this is traditionally done using square brackets. Consider a page with the sentence "Fred ate the cracker. He then said he liked apples and fish."; it could be quoted as follows:
<blockquote> <p>[Fred] then said he liked [...] fish.</p> </blockquote>
Attribution for the quotation, if any, must be placed outside the
  blockquote element.
For example, here the attribution is given in a paragraph after the quote:
<blockquote> <p>I contend that we are both atheists. I just believe in one fewer god than you do. When you understand why you dismiss all the other possible gods, you will understand why I dismiss yours.</p> </blockquote> <p>— Stephen Roberts</p>
The other examples below show other ways of showing attribution.
The cite IDL
  attribute must reflect the element's cite content attribute.
Here a blockquote element is used in conjunction
   with a figure element and its figcaption
   to clearly relate a quote to its attribution (which is not part of
   the quote and therefore doesn't belong inside the
   blockquote itself):
<figure> <blockquote> <p>The truth may be puzzling. It may take some work to grapple with. It may be counterintuitive. It may contradict deeply held prejudices. It may not be consonant with what we desperately want to be true. But our preferences do not determine what's true. We have a method, and that method helps us to reach not absolute truth, only asymptotic approaches to the truth — never there, just closer and closer, always finding vast new oceans of undiscovered possibilities. Cleverly designed experiments are the key.</p> </blockquote> <figcaption>Carl Sagan, in "<cite>Wonder and Skepticism</cite>", from the <cite>Skeptical Enquirer</cite> Volume 19, Issue 1 (January-February 1995)</figcaption> </figure>
This next example shows the use of cite alongside
   blockquote:
<p>His next piece was the aptly named <cite>Sonnet 130</cite>:</p> <blockquote cite="http://quotes.example.org/s/sonnet130.html"> <p>My mistress' eyes are nothing like the sun,<br> Coral is far more red, than her lips red,<br> ...
This example shows how a forum post could use
   blockquote to show what post a user is replying
   to. The article element is used for each post, to mark
   up the threading.
<article>
 <h1><a href="http://bacon.example.com/?blog=109431">Bacon on a crowbar</a></h1>
 <article>
  <header><strong>t3yw</strong> 12 points 1 hour ago</header>
  <p>I bet a narwhal would love that.</p>
  <footer><a href="?pid=29578">permalink</a></footer>
  <article>
   <header><strong>greg</strong> 8 points 1 hour ago</header>
   <blockquote><p>I bet a narwhal would love that.</p></blockquote>
   <p>Dude narwhals don't eat bacon.</p>
   <footer><a href="?pid=29579">permalink</a></footer>
   <article>
    <header><strong>t3yw</strong> 15 points 1 hour ago</header>
    <blockquote>
     <blockquote><p>I bet a narwhal would love that.</p></blockquote>
     <p>Dude narwhals don't eat bacon.</p>
    </blockquote>
    <p>Next thing you'll be saying they don't get capes and wizard
    hats either!</p>
    <footer><a href="?pid=29580">permalink</a></footer>
    <article>
     <article>
      <header><strong>boing</strong> -5 points 1 hour ago</header>
      <p>narwhals are worse than ceiling cat</p>
      <footer><a href="?pid=29581">permalink</a></footer>
     </article>
    </article>
   </article>
  </article>
  <article>
   <header><strong>fred</strong> 1 points 23 minutes ago</header>
   <blockquote><p>I bet a narwhal would love that.</p></blockquote>
   <p>I bet they'd love to peel a banana too.</p>
   <footer><a href="?pid=29582">permalink</a></footer>
  </article>
 </article>
</article>
  This example shows the use of a blockquote for
   short snippets, demonstrating that one does not have to use
   p elements inside blockquote
   elements:
<p>He began his list of "lessons" with the following:</p> <blockquote>One should never assume that his side of the issue will be recognized, let alone that it will be conceded to have merits.</blockquote> <p>He continued with a number of similar points, ending with:</p> <blockquote>Finally, one should be prepared for the threat of breakdown in negotiations at any given moment and not be cowed by the possiblity.</blockquote> <p>We shall now discuss these points...
Examples of how to
  represent a conversation are shown in a later section; it is not
  appropriate to use the cite and blockquote
  elements for this purpose.