This indicates that XML document data is available.
As well as the JScript syntax, there are two alternatives:
Inline HTML:
<ELEMENT ondataavailable="myEventHandler" ... >
Named Script (IE Only):
<SCRIPT FOR = object EVENT = ondataavailable>
The ondataavailable event indicates that XML document data is available. This can be useful when handling asynchronous data as it enables you to start processing as soon as data becomes available, in parallel with downloading. The ondataavailable event fires each time a new chunk of data arrives.
The handler for this event can be explicitly set with the ondataavailable property.