In the first chapter of this book, you were introduced to the basic concepts behind Comet and subsequently learned about the individual building blocks that fit together to form a working Comet stack. You saw in Chapter 2 how to open long-lived requests using
XmlHTTPRequest or an
iframe. Chapter 3 demonstrated how to keep requests open on the server and push out data as it arrives.
However, you also learned about some of Comet's complexities, such as the limit of two concurrent requests imposed by certain browsers, and some of the server-side scalability obstacles that long-lived requests present.
If you were feeling adventurous, you could now develop your own Comet application from scratch. Inevitably though, you'd ...