Optimal Placement of Script Tags in HTML Markup Introduction When integrating JavaScript into HTML documents, the appropriate placement of tags has long been a subject of debate. This article explores the best practices for tag placement, addressing the misconceptions associated with the <head> and <body> sections.</p> <h3>Historic Misconceptions</h3> <p>In the past, it was advised against placing <script> tags in the <head> section. However, this recommendation was outdated and stemmed from the potential for scripts to block page rendering while being parsed.</p> <p>Conversely, placing <script> tags at the beginning of the <body> section was also deemed undesirable. This was because the browser would have to parse the JavaScript before fully rendering the page, leading to potential performance issues.</p> <h3>Modern Best Practices</h3> <p>Today, the optimal placement for <script> tags is in the <head> section. This allows browsers to start downloading scripts immediately without blocking the parsing of the rest of the document.</p> <p>To avoid the blocking behavior associated with script parsing, browsers now support the async and defer attributes.</p> <h3>Using async and defer Attributes</h3> <p><strong>Async:</strong> Scripts with the async attribute are executed asynchronously, meaning the browser can continue parsing the document while the script downloads and executes.</p> <p><strong>Defer:</strong> Scripts with the defer attribute are executed in the order they appear in the document but only after the entire document has been parsed.</p> <p><strong>Modules:</strong> JavaScript modules with type="module" load asynchronously and are treated like deferred scripts.</p> <h3>Conclusion</h3> <p>By utilizing the async, defer, or module attributes and placing <script> tags in the <head> section, website developers can optimize page loading speeds and improve user experience.</p> <h3>References</h3> <ul> <li>[async vs defer attributes](https://www.html5rocks.com/en/tutorials/speed/script-loading/)</li> <li>[Efficiently load JavaScript with defer and async](https://developers.google.com/web/fundamentals/performance/critical-rendering-path/defer-loading-javascript)</li> <li>[Remove Render-Blocking JavaScript](https://www.w3.org/TR/html5/scripting-1.html#remove-render-blocking-javascript)</li> <li>[Async, Defer, Modules: A Visual Cheatsheet](https://addyosmani.com/blog/async-defer-modules-explained/#~a-visual-explanation)</li> <li>[<script>: type attribute](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/script)</li> </ul>