Using a function to add a style - properties

Question

I'm using the same stuff i usually use to make functions work but for some reason it says "Cannot read property 'add' of undefined" and I have tried everything I know.
<input type=button id=b1 value="start" onclick=abc()>
<script>
function abc() {
document.getElementById("p2").classlist.add("hidden")
document.getElementById("pic1").classlist.remove('hidden')
document.getElementById("p1").classlist.add("hidden")
window.setimeout(sub1, 1000)
}
</script>

Answer 1

classlist should be classList. Also, where you have setimeout, that should be setTimeout. Lastly, you are missing some quotation marks around property values for your input element, and missing semicolons at the end of your individual statements.
div {
border: 1px solid #000;
margin: 1rem 0;
padding: .5rem;
}
.hidden {
display: none;
}
<input type="button" id="b1" value="start" onclick="abc()">
<script>
function abc() {
document.getElementById("p2").classList.add("hidden");
document.getElementById("pic1").classList.remove("hidden");
document.getElementById("p1").classList.add("hidden");
window.setTimeout(sub1, 1000);
}
function sub1() {
console.log("called!");
}
</script>
<div id="p2">This is the p2 div</div>
<div id="pic1" class="hidden">This is the pic1 div</div>
<div id="p1">This is the p1 div</div>