In fact, this is the work done by the front end, not the work done by the back end
The backend can count up to the time from client request to server response, but the backend cannot count the resources statically referenced by the page and the execution time of some front-end code business logic
On the contrary, the front-end can count the processing time of the server and the time of the front-end processing its own business
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
In fact, this is the work done by the front end, not the work done by the back end
The backend can count up to the time from client request to server response, but the backend cannot count the resources statically referenced by the page and the execution time of some front-end code business logic
On the contrary, the front-end can count the processing time of the server and the time of the front-end processing its own business
At the beginning of page rendering, get the current time from js, and then after window.onload, get the current time and compare it? (I guess...)