JSFiddle - React, Tailwind, and code Playground

HTML

<div class="once-per-session">Once per session.</div>

CSS

.once-per-session {
  border:1px solid black;
  border-radius:5px;
  padding:10px;
  background-color:lightgreen;
}

JavaScript

if (sessionStorage.beenHere) {
  document.querySelector(".once-per-session").style.display = "none";
}
sessionStorage.beenHere = true;