HTML and CSS Reference
18.104.22.168. Cue properties
Cue properties let you insert audible cues before or after an element.
For example, you might precede each chapter in a book with a musical
cue, or denote the end of quoted text with an audible tone.
The cue-before and cue-after properties take as their value the URL of a
sound file, which the browser loads and plays before or after the styled
document element, respectively. Technically, the sound can be of any
duration, but the presumption is that audible cues are short and nonin-
trusive, enhancing the audio experience instead of overwhelming it.
Use the cue property to set both the cue-before and cue-after properties
at once. If you provide one URL value, it sets both cue sounds; with two
values, the first sets the cue-before sound and the second sets the cue-
22.214.171.124. Audio mixing
To create a more pleasant listening experience, you may want to play
background music during a spoken passage. The play-during property
meets this need. Its values are the URL of the sound file and several
keywords that control playback.
The repeat keyword repeats the background audio until the spoken con-
tent is complete. If you don't use this keyword, the background sound
plays once, even if it is shorter than the spoken content. A background
sound that is longer than the spoken content ends when the content
The mix keyword tells the CSS2-conscious browser to meld the back-
ground sound with any other background sounds that may be playing
as defined by some parent element. If you don't use this keyword,
child-element background sounds replace parent-element background
sounds, which resume when the current element has finished.