JavaScript plays a crucial role in website interactivity, but poorly optimized JavaScript code can significantly impact web performance. To enhance JavaScript performance, consider the following strategies:

1. Utilize async and defer attributes: By adding the 'async' or 'defer' attribute to the script tag, browsers can load JavaScript asynchronously, preventing it from blocking other elements from rendering. While 'async' allows immediate loading and execution, 'defer' ensures the script is executed after the HTML document is parsed.

Example:

<script async src='script.js'></script>

2. Employ efficient coding practices: Optimize your JavaScript code by minimizing the use of loops and unnecessary DOM manipulations. Identify performance bottlenecks and refactor or optimize your code accordingly.

Example:

for (let i=0; i < array.length; i++) {
  // Perform operations
}

// Optimized code:
const length = array.length;
for (let i=0; i < length; i++) {
  // Perform operations
}

3. Leverage browser caching: If you include scripts from external sources, such as CDNs, configure caching headers to enable the browser to cache the script file. This reduces the number of requests sent to the server, leading to faster page load times.

Example:

// Set caching headers for external script
<script src='https://example.com/script.js' cache-control='public, max-age=604800'></script>