Webpage content display after page display progress bar is loaded _ javascript skills

The page display progress bar when a webpage is loaded (the webpage content is displayed when the webpage is loaded). This effect is very common in Web browsing. This article also introduces an implementation method, if you want to know more, you can refer to the fact that there are many webpage loading progress bars on the Internet, but most of them are fixed.
When a large amount of data is queried below, the webpage loading is slow. When the webpage is loaded, the progress bar is displayed. When the webpage is loaded, the progress bar disappears and the content already loaded is displayed.

The Code is as follows: