Hi Jess –
Not sure I 100% follow – is there an acf_form() on the page. I believe the acf javascript obj gets loaded with the header scripts. <?php acf_form_head(); ?>
It wouldn’t be hard to just write some jquery/javascript to basically change a var if the user changes a field, and throw a warning like this.
window.onbeforeunload = function(){
if (change) {
return 'Are you sure you want to leave?';
}
};
See: http://stackoverflow.com/questions/7080269/javascript-before-leaving-the-page