where can I test the execution times of a javascript code?

Question

I know what I can do it with console.time or Date.now, but I would like to know some program or web to test the time
without having to write lines of code between the main algorithm

Answer 1

Using performance.now() function

Answer 2

You just need to print time before the execution and after the execution and check the difference. I don't think that this is so many lines of code.