Why shouldn't `&apos;` be used to escape single quotes?
As stated in, [When did single quotes in HTML become so popular?][1] and [Jquery embedded quote in attribute][2], the Wikipedia entry on HTML says the following:

> The single-quote character ('), when used to quote an attribute value, must also be escaped as `&#x27;` or `&#39;` (should NOT be escaped as `&apos;` except in XHTML documents) when it appears within the attribute value itself.

Why shouldn't `&apos;` be used?  Also, is `&quot;` safe to be used instead of `&#34;`?

  [1]: http://stackoverflow.com/questions/242766/when-did-single-quotes-in-html-become-so-popular
  [2]: http://stackoverflow.com/questions/1263141/jquery-embedded-quote-in-attribute
Why shouldn't `&apos;` be used to escape single quotes?
===

As stated in, [When did single quotes in HTML become so popular?][1] and [Jquery embedded quote in attribute][2], the Wikipedia entry on HTML says the following:

> The single-quote character ('), when used to quote an attribute value, must also be escaped as `&#x27;` or `&#39;` (should NOT be escaped as `&apos;` except in XHTML documents) when it appears within the attribute value itself.

Why shouldn't `&apos;` be used?  Also, is `&quot;` safe to be used instead of `&#34;`?

  [1]: http://stackoverflow.com/questions/242766/when-did-single-quotes-in-html-become-so-popular
  [2]: http://stackoverflow.com/questions/1263141/jquery-embedded-quote-in-attribute