Evil Firefox Error — “A parameter or an operation is not supported by the underlying object”

Question

I\'m trying to figure out what is going on here. I\'ve been at it for hours now and can\'t seem to get a grip on why this is happening.

I\'m making a few AJAX calls, and

Answer 1

this is the real solution by Diogo Cardoso, the xhr object or parent seems to lack a toString() method

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