HTMLify

const p = document.getElementById("p");
const searchBtn = document.getElementById("searchBtn");

searchBtn.addEventListener("click", () => {
  let input = document.getElementById("input").value;

  if (input !== "") {
    let regExp = new RegExp(input, "gi");
    p.innerHTML = p.textContent.replace(regExp, "<mark>$&</mark>");
  }
});