lative 

##  The problem

In the past we would resolve the relative URL against the current global, for
example:

js

    
    
    let absolute = new URL(relative, window.location.href);
    

This is not a problem as such. It is just that different APIs that exhibit
this kind of behavior were doing it inconsistently with the behavior defined
in the spec, which could lead to problems further down the line.

##  The solution

In Firefox 60 onwards, Mozilla resolves the relative URL against the global
that owns the ` fetch() ` function being used (see [ Firefox bug 1432272
](https://bugzil.la/1432272) ). So in the case described above, it is resolved
against the iframe's location:

js

    
    
    let absolute = new URL(relative, frame.contentWindow.location.href);
    

There is a lot of discussion in progress about getting new specs to align with
this behavior change, to mitigate potential problems going forward.

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