How to pause a script just for a fraction of a second in PHP using the SLEEP() function?

Question

sleep(1);   #waits/sleeps for one second then continue running the script

Q1. How to make this 1/100 of a second? which of these work: 0,01

Answer 1

What you are looking for is usleep() or time_nanosleep().

As for your second question, all these methods come with a high level of precision however I would advise you to test on your specific system if it's critical.