HTML JavaScript

Example

My First JavaScript

Try it Yourself »

---

The HTML <script> Tag

The <script> tag is used to define a client-side script (JavaScript).

The <script> element either contains scripting statements, or it points to an external script file through the srcattribute.

Common uses for JavaScript are image manipulation, form validation, and dynamic changes of content.

To select an HTML element, JavaScript very often use the document.getElementById(id) method.

This JavaScript example writes "Hello JavaScript!" into an HTML element with id="demo":

Example

<script>
document.getElementById("demo").innerHTML = "Hello JavaScript!";</script>

Try it Yourself »

A Taste of JavaScript

Here are some examples of what JavaScript can do:

JavaScript can change HTML content

document.getElementById("demo").innerHTML = "Hello JavaScript!";

Try it Yourself »

JavaScript can change HTML styles

document.getElementById("demo").style.fontSize = "25px";
document.getElementById("demo").style.color = "red";
document.getElementById("demo").style.backgroundColor = "yellow";

Try it Yourself »

JavaScript can change HTML attributes

document.getElementById("image").src = "picture.gif";

Try it Yourself »