for example i want to call a js function at 10.00.00.00 am how can i do?
Assuming the code is located on a web page that will be loaded before 10:00 and will still be viewed at 10:00, you can use setTimeout()
to set up a timed event. the function takes some JS statement to execute, and the number of milliseconds before it should execute. You can find this second part pretty easily with the built-in date functions.