[xul-interop] Why is QueryInterface needed?

[Tom B. <bri...@gm...>]

Hi all!

I saw many code examples using QueryInterface, most when it's a very
complicated thing to do. And it's doc says:

The QueryInterface method provides runtime type discovery.

But we use it with javascript, that is dynamically typed language, so why is
it needed?


Best,

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Wellington B. de Carvalho
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