innerHTML

index.html

<ul>
  <li>salt</li>
  <li>pepper</li>
</ul>

<p>Today is a <span id="day">bad</span> day</p>

innerhtml.markdown

innerHTML

A Pen by Bre'Ana Deen on CodePen.

License.

script.js

var list = document.getElementsByTagName("ul")[0];
list.innerHTML += "<li>garlic</li>";

var day = document.getElementById("day");
day.innerHTML = "good";