During a server-push animation, an HTTP server sends the browser one animation
frame at a time.
The G Web Server has built in support for generating server-push animations from
the output of a CGI. The animation is invoked through the .spool URL. The
URL specifies which CGI is used for generating the individual images. The server
then repeatedly calls the CGI and sends its output to the browser.
In this example, the CGI simply returns the contents of GIF files inside its directory.
The CGI uses a cookie to keep track of which frame should be returned whenever its
called.
The following is an embedded image of a server-push animation produced by the CGI
/cgi-bin/examples/blob.vi. The CGI is called approximately twice a second
for a duration of 30 seconds. The HTML code for this image is
<IMG src="/.spool?/cgi-bin/examples/animate/blob.vi&refresh=0.5&lifespan=30">