HTML, CSS, and JavaScript: How They Work Together

Most beginner web projects become easier to understand when you separate the three jobs of the browser.

HTML: structure

<button id="saveButton">Save</button>

HTML describes the elements and content on a page.

CSS: presentation

button {
  padding: 10px;
}

CSS controls appearance and layout.

JavaScript: behavior

document.getElementById("saveButton").addEventListener("click", () => {
  alert("Saved!");
});

JavaScript responds to events and changes the page or communicates with services.

The simple mental model

Think of HTML as the structure, CSS as the appearance, and JavaScript as the behavior.

Then continue with JavaScript Basics.