Minimising mainstream thread work is a Page speed recommendation which was included in the Web Diagnostic Area performance report. You might have come across this suggestion while testing your WordPress site. For understanding main thread work, we have to recollect everything that happens when we load a page content.
The browser requests the server in the first place. Once the server responds to the browser with the requested content, the browser begins to analyse and parse the HTML code of the page and build a DOM Tree. This is called the HTML structure of the web page. This is that point where the browser can render and display the content.
This process of rendering and parsing the content is the browser’s main thread. The browser meets with the render blocking resources that slow down the page loading process. It makes the main thread get busy and blocked. This is why the web page fails to be interactive and cannot either respond to any kind of user interaction.
The prime issue of a busy main thread is JavaScript along with CSS files playing an important role. The browser should not come across these files in the process of parsing and code rendering. The Javascript and CSS files are render blocking in nature and have to be removed for improving page insights score.
SEO For Increasing Page Insights Scores
The recommendation of the Page Speed is evenly split into different sections. The categories to work more amongst all are:-
- Evaluation of script
- Compilation and parsing of the script
- Parsing HTML and CSS codes.
When the main thread works on the website code, it fails in handling the user requests simultaneously. Therefore, if work of the main thread takes more than 4 seconds of time, the loading speed of the page will get slow along with poor UX.
To improve the page insights score through the minimisation of main thread work you have to do the things listed below.
- You will have to reduce the CSS, HTML, JavaScript files by using inlining or deferring methods of reducing file sizes.
- Remove the unused code from your site. Similar to minimising code, you can consider the inlining or deferring patterns in the best possible manner which can work for your webpage. You can also use tools like Chrome Dev Tools. It will help you to find unused JavaScript and CSS code.
- Implement the process of browser caching. This process involves saving and storing copies of the previously loaded web resources . This is so that the browser does not need to reload them every time you visit. You can use tools like W3 Total Cache. They are suitable for WordPress websites.
- Implement the code splitting Process. This process is a high-level advanced technique which involves splitting the JavaScript into small bundles for execution. It can easily access them when required instead of having the web browsers to load all the code for making the web page look interactive. You can use the webpack tool to implement code splitting procedure.