This question both examines the depth of technology and examines the breadth of technology, in fact, it is quite difficult to answer well.
After typing a URL in the address bar, the browser makes a request to the server to request the content of the URL page, and then the server receives the request to process the request, and then returns the processing result to the browser in the form of an HTML file, and finally the browser parses the returned HTML file. If the browser finds that the returned page contains a CSS file, the browser requests the CSS file to the server again, and so on, the browser requests the JS file to the server again, and then, when it finds the file, it requests the image file from the server, and then puts the files in the corresponding location. The content of the Web page is not a one-time request can be taken out of all the files, but 1.1 points of the extracted. Therefore, when the Internet speed is relatively slow, the content of the Web page may be the first display of a contour, and then the image and other elements of a little more display.
Reference
What happens in the process from the input URL to the page load complete
What happened to typing a URL from the address bar and showing it to the Web?