Async, short for asynchronous, is a term used to describe the way in which some JavaScript code is executed. Async code is executed in parallel with other code on a web page, rather than in a linear sequence. This can improve the performance and loading speed of a web page, as it allows different parts of the page to load and execute at the same time.
In SEO, async is important because it can improve the performance and loading speed of a website. Search engines, including Google, use page speed as a ranking factor in their algorithms, so a faster-loading website is likely to rank higher in search results than a slower-loading website.
To use async, webmasters can add the “async” attribute to the script tags that include JavaScript code on their website. This tells the browser to execute the code asynchronously, rather than in a linear sequence. This can improve the performance and loading speed of the website, and may help to improve its search engine ranking.
Overall, async is a useful technique for improving the performance and loading speed of a website in the context of SEO. By adding the “async” attribute to JavaScript code on a website, webmasters can improve the website’s loading speed, which may help to improve its search engine ranking and visibility to users.