JavaScript script tag

The <script> tag in JavaScript is used to embed or reference scripts in an HTML document. It tells the browser that the enclosed code is JavaScript and should be executed.

JavaScript is implemented by adding <script>… </script> tag within the HTML tag in a web page. The <script> tag instructs the browser about the JavaScript code and to process the script separately.

<script> tag can be inserted within the web page in:

• head section
• body section

Basic Syntax

The basic syntax is as follows:

<script>

  // JavaScript code goes here 
  alert("Hello, World!");

</script>

Script in<head> section

<head>

        <script....>

         //Your JavaScript code goes here

        </script>

</head>

Script in <body> section

<body>

       <script.....>

       // Your JavaScript code goes here

       </script>

</body>

<script> tag has the following attributes

language

The language attribute is set to value “JavaScript”, which tells the browser that the scripting language is JavaScript.

type

The type attribute tells the browser that the script is in plain text and the text is organized in the format of a JavaScript. This is for browser information– how to read the JavaScript code.

<script language="JavaScript" type ="text/javascript">

      document.write("Hello, world!")

</script>

src

Specifies the external JavaScript file to load.

<script src="script.js"></script>

async

Loads the script asynchronously (doesn’t block HTML parsing). Good for independent scripts like ads or analytics.

<script src="analytics.js" async></script>

defer

Loads the script in order, but execution is delayed until the HTML is fully parsed. Great for DOM-related scripts.

<script src="main.js" defer></script>