From http://www.w3schools.com (Copyright Refsnes Data)
The volume property is used only in Aural Stylesheets.
The aural rendering of a document combines sounds and voices to go through the content of a document. Aural presentation occurs often by converting the document to plain text and then feeding this to a screen reader.
Situations and markets for listening to information could be:
The volume property specifies the volume of the speaking voice. User agents should allow the volume to be changed by the listener.
| Value | Description |
|---|---|
| number | A number between 0 and 100. 0 represents the lowest possible volume and 100 represents the maximum volume |
| % | A % calculated relative to the inherited value |
| silent | No sound at all. Note: silent is not the same as 0 |
| x-soft | Same as 0 |
| soft | Same as 25 |
| medium | Same as 50 |
| loud | Same as 75 |
| x-loud | Same as 100 |
From http://www.w3schools.com (Copyright Refsnes Data)