HTML JavaScript

HTML JavaScript – JavaScript makes HTML pages more dynamic and interactive.

The HTML <script> Tag

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

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

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

To select an HTML element, JavaScript most often uses the document.getElementById() method.


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

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

Tip: You can learn much more about JavaScript in our JavaScript Tutorial.

A Taste of JavaScript

Here are some examples of what JavaScript can do:


JavaScript can change content:

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


JavaScript can change styles:

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


JavaScript can change attributes:

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

The HTML <noscript> Tag

The HTML <noscript> tag defines an alternate content to be displayed to users that have disabled scripts in their browser or have a browser that doesn’t support scripts:


document.getElementById("demo").innerHTML = "Hello JavaScript!";
<noscript>Sorry, your browser does not support JavaScript!</noscript>

HTML Script Tags

Tag Description
<script> Defines a client-side script
<noscript> Defines an alternate content for users that do not support client-side scripts
For a complete list of all available HTML tags, visit our HTML Tag Reference.

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