title: HTML character entities and character encoding set
body: <p>When including HTML entities in an HTML document, do the entities need to be from the same character encoding set that the document is specified to be using?</p>
  
  <p>For example, if I am going to use the copyright sign in an HTML document that is specified as <code>UTF-8</code>, is it necessary to use the Unicode HTML entity (<code>&amp;#x00A9;</code>) or is it okay to use other entities, such as the <code>ASCII</code> HTML entity (<code>&amp;#169;</code>)?</p>
  
  <p>Please explain your answer. I am aware that it will "work", but is there a case where it will not work?</p>
  
  <p>Thanks!</p>