HTML JavaScript

JavaScript makes HTML pages more dynamic and interactive.

Example

My First JavaScript

Click me to display Date and Time

The HTML <script> Tag

The <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”:

Example

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

A Taste of JavaScript

Here are some examples of what JavaScript can do:

JavaScript can change HTML content

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

JavaScript can change HTML styles

	document.getElementById("demo").style.fontSize = "25px";

	document.getElementById("demo").style.color = "red";

	document.getElementById("demo").style.backgroundColor = "yellow";

JavaScript can change HTML attributes

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

The HTML <noscript> Tag

The <noscript> tag is used to provide an alternate content for users that have disabled scripts in their browser replica men watches or have a browser that doesn’t support client-side scripts:

Example

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

	<noscript>Sorry, your browser does not support JavaScript!</noscript>

<>

HTML Script Tags