Creating an external JavaScript file offers numerous benefits, such as code reusability, improved readability, and increased webpage loading speed. An external JavaScript file must be saved with the .js extension. Here’s an example of how to create and use an external JavaScript file.
Using an external JavaScript file is a good practice for keeping your code organized and reusable
<!DOCTYPE html>
<html>
<head>
<title>JavaScript Example</title>
<script src="script.js" type="text/javascript"></script>
</head>
<body>
<h3>JavaScript Example</h3>
<script type="text/javascript">
displayMessage();
</script>
</body>
</html>
<script>
function displayMessage() {
document.write("JavaScript is a simple language for learners.");
}
</script>
1. Code Reusability: A single JavaScript file can be used across multiple HTML pages, reducing redundancy.
2. Easy Code Readability: Separating JavaScript from HTML makes both files easier to read and maintain.
3. Time-Efficient: Web browsers cache external JavaScript files, which reduces page loading times for subsequent visits.
4. Parallel Work: Designers can focus on HTML and CSS while developers work on JavaScript, minimizing code conflicts.
5. Reduced Code Length: Only the location of the external JavaScript file needs to be specified in the HTML.
1. Code Theft: The URL of the external JavaScript file can be used to download the code.
2. Dependency Issues: If two JavaScript files are dependent on each other, a failure in one can affect the other.
3. Additional HTTP Request: An extra HTTP request is needed to fetch the external JavaScript file.
4. Global Impact of Changes: Changes in the JavaScript file can cause unexpected results in all dependent HTML files.
5. Small Code Segments: For small amounts of JavaScript code, it might be more practical to include it directly within the HTML file.