viewport.html

<dt><dfn id="dfn-viewport">viewport</dfn></dt>
<dd>
   
   <p>object in which the <a>user agent</a> presents content</p>
   
   <p class="note">The user agent presents content through one or more viewports. Viewports include windows, frames,
      loudspeakers, and virtual magnifying glasses. A viewport may contain another viewport
      (e.g., nested frames). Interface components created by the user agent such as prompts,
      menus, and alerts are not viewports.
   </p>
   
   <p class="note">This definition is based on <a href="https://www.w3.org/TR/WAI-USERAGENT/glossary.html">User Agent Accessibility Guidelines 1.0 Glossary</a> [[UAAG10]].
   </p>
   
</dd>