How Does the SMIL show Attribute Control Link Windows?

The show attribute in Synchronized Multimedia Integration Language (SMIL) controls the presentation context when a user activates a hyperlink, determining whether the destination resource replaces the current presentation, loads into a new window, or pauses the current context. Defined primarily on linking elements like <a> and <area>, this attribute accepts three standard values: replace, new, and pause. Understanding how these values interact with the presentation player allows developers to manage multimedia playback continuity and window management effectively.

Standard Values of the show Attribute

SMIL provides explicit values for the show attribute to manage how user agents render linked content:

replace: This is typically the default behavior. Activating the link replaces the current presentation in the existing playback window or context. The current presentation terminates its timeline, and the target document loads into the same space.
new: Activating the link opens a separate, new presentation context or window for the target resource. The original presentation continues playing in its existing window without interruption, running concurrently with the newly opened content.
pause: The destination resource opens in a new presentation context, but the source presentation is paused at the moment of activation. Once the user finishes interacting with or closes the destination content, playback of the original presentation can resume from where it was suspended.

Syntax and Implementation

The show attribute is declared directly inside linking tags within the SMIL document body:

<smil xmlns="http://www.w3.org/ns/SMIL">
  <body>
    <par>
      <video src="intro.mp4" />
      <!-- Link configured to open in a separate window without stopping current video -->
      <a href="https://example.com/details.smil" show="new">
        <text src="caption.html" region="subtitleArea" />
      </a>
    </par>
  </body>
</smil>

Comparison with HTML Linking

While HTML uses the target attribute (such as target="_blank" or target="_self") to direct link targets to specific frames or windows, SMIL utilizes show from the XML Linking Language (XLink) framework. This design reflects the temporal and multimedia nature of SMIL, where window management must coordinate directly with presentation timelines, resource playback, and synchronization states.