In this example below you will see how to do a FirstPen with some HTML / CSS and Javascript

This awesome code was written by JGall, you can see more from this user in the personal repository.
You can find the original code on
Copyright JGall ©
  • HTML
  • CSS
  • JavaScript
    <h1>Hello world</h1>
<p id="demo"><strong>This is a simple codepen demo</strong></p>

/*Downloaded from */
    h1 {
  color: red;

p {
  font-family: arial;
  color: blue;
  font-size: 20px;

/*Downloaded from */
    var x = document.getElementById("demo");
x.innerHTML = "This is the power of javascript";