It's true I only need one card, and then I put the text I want in it and either display it or hide it.
<div id="thecard" style="position:fixed;left:0px;top:0px;right:0px;bottom:0px;color:pink;background-color:lightgrey;font-size:0px;display:none"></div><div id="cardarea" style="display:none"></div>
function showthecard(cardnumber) {
var card = document.getElementById("thecard")
card.style.left = "100px"
card.style.top = "100px"
card.style.right = "100px"
card.style.bottom = "100px"
area = (window.innerWidth - 200) * (window.innerHeight - 200)
document.getElementById("cardarea").innerHTML = area
if (cardnumber === 1) {addtextforcard1()}}
