how to load css asynchronously

Asynchronous loading of CSS has become quite popular in recent times as it enables faster and more efficient loading of website content. The traditional method of loading CSS files involves loading them synchronously which leads to unnecessary delays and a slower user experience. In this article, we will discuss how to load CSS asynchronously and improve the loading speed of your website.The problem with synchronous loading of CSSWhen a web page is loaded, the browser must first download all the assets including HTML, CSS and JavaScript files, images, and other resources before it can begin rendering the page. While HTML files are loaded progressively and render the content as it appears on the page, CSS files need to be loaded first before the rendering process begins. This is known as the CSS blocking problem.The traditional method of loading CSS files involves loading them synchronously which means that the browser will wait for them to be fully downloaded before it begins rendering the page content. As a result, the larger the CSS file, the longer the wait time for the user. This can lead to a slower user experience which can affect the bounce rate and overall engagement on the website.The benefits of asynchronous loading of CSSAsynchronous loading of CSS allows the browser to fully utilize its parallel processing capabilities to download the CSS files while rendering the content of the page at the same time. This results in a faster and more efficient loading of the website content. Additionally, it also lowers the impact of CSS files on the performance of the website.How to load CSS asynchronously1. Use the HTML5 async attributeThe HTML5 specification introduced the async attribute for loading scripts asynchronously. However, it can also be used to load external CSS files asynchronously. To do this, simply add the async attribute to the link element in the head section of your HTML file.``````2. Use JavaScript to load CSS files asynchronouslyThis method involves using JavaScript to load the CSS file asynchronously. The benefit of this method is that it gives you more control over the loading process which can be useful if you’re dealing with complex stylesheets with multiple dependencies.```var link = document.createElement('link');link.rel = 'stylesheet';link.type = 'text/css';link.href = 'style.css';link.media = 'all';document.getElementsByTagName('head')[0].appendChild(link);```3. Use a CSS loaderThere are various third-party libraries available that offer the functionality of loading CSS files asynchronously. Some of the popular ones are loadCSS, AsyncCSS, and LABjs. These libraries can be easily integrated into your project and give you more flexibility and control over the loading of your CSS files.In conclusionAsynchronous loading of CSS files is an effective way of improving website performance by reducing load times and improving the user experience. There are various methods available to load CSS files asynchronously such as using the HTML5 async attribute, JavaScript, or third-party libraries. It is important to choose the method that is most suitable for your project and optimize it for the best results. By following these practices, you can significantly improve the performance of your website and achieve a faster, smoother user experience.