A function that determines how the preload itself works. It must take a list of URLs as an argument and return void.
It's default behavior is to call window.SpeedKit.preload() with the URLs. This can be overwritten to manipulate
or map urls or call a custom preload function entirely.
A function that determines how the preload itself works. It must take a list of URLs as an argument and return void. It's default behavior is to call
window.SpeedKit.preload()with the URLs. This can be overwritten to manipulate or map urls or call a custom preload function entirely.Defaults to
undefined.