Looking for a event listener for before page load

Does anyone at all know a way to do a ajax GET call before the page has loaded. I wondered if there was a specific event listener from knack that I can possibly use. I want to create a dark theme and have the option stored in the accounts database ie dark theme active. I can do a GET ajax call but this is only after the scene, view etc is rendered

Hi Jonathan, 

I don't think it's possible to do a GET request prior to the page loading. I have done custom themes in the past, but I used the users local storage and saved all of the styles on the users machine. It worked pretty well. 

Best Regards,