Problem with getElementById()

I want to get an element by its unique id. I set the attribute "id" to the
element. But when I called Document.getElementById(), it returns null. I'm
using Apache Batik DOM implementation. Does anybody ever used it? Or how to
use it in other packages like Xerces? I looked at Xerces API, but didn't
find any useful information.

Thanks a lot!

Gang Li
Design Engineer
EMC Corporation

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