246996016-HTML5-Step-by-Step

310 Chapter 16
Including External Content in Web Pages
HTML5 introduced the tag which enables you to push external server
content to a Web page. The model is called “push” in contrast to the traditional “pull”
model that is used on the Web, where the Web browser always requests information
from the server. Like the element, as of this writing the tag is
not widely supported in Web browsers; therefore, it’s of limited use for practical Web
programming until new browsers appear and are widely adopted. For more information
on , see http://www.whatwg.org/specs/web-apps/current-work/.
Another method for including external data (and multimedia in this case) is the
tag. Unlike , the tag has wide support across browsers. Even
though wasn’t formalized in the HTML specification until version 5, people
have been using the tag for years due to its cross-browser compatibility.
The tag is frequently used to insert elements such as Flash or background
audio on a Web page. The tag uses several attributes, such as src to define the
resource to embed, type to define the type of content being embedded, and height and
width to set the height and width of the element, respectively.
Using to embed an MP3 file is as simple as this:
Just as when including any multimedia or other objects in a page, playback is dependent
on the client. While my browser supports playing an MP3 audio file, there’s no guarantee
that another visitor will be able to do so. Therefore, I recommend using only
when absolutely necessary.