Show an element hidden on launch

Alright, I think I solved it, though I’m not entirely sure why it works like that:

$w.onReady( () =>
{
$w('#email').onClick( () => {
wixWindow.copyToClipboard("email address")
 .then( () =>
 {
        $w("#popup").show();
        setTimeout(()=>{
        $w("#popup").hide();
        },3000);
 });
 });
});

Thanks for your help again.