A function that gets called on preload candidate element. It must take the HTMLElement as an argument and return
the matching URl as a string. This is useful when the URL is not clearly written in an attribute on the element, like
for links that work with onClick.
A function that gets called on preload candidate element. It must take the HTMLElement as an argument and return the matching URl as a string. This is useful when the URL is not clearly written in an attribute on the element, like for links that work with
onClick.Defaults to
undefined.