Does it need to automatically render whether today is Friday... something like this is silly but kinda works -- requires you to set the date though which I'm not sure is allowed.
<input type="date" min="0001-01-05" step="7" value="2023-07-03"> // valid for all Fridays starting 1AD
Then you can use some css when invalid:
input:invalid {
background: red;
}
or whatever other styling you want, maybe slap some content on another element... you get the point
