selenium.setSpeed

1. takes a single argument in string format

ex: selenium.setSpeed("2000") - will wait for 2 seconds

2. Runs each command in after setSpeed delay by the number of milliseconds mentioned in setSpeed.

thread.sleep

1. takes a single argument in integer format

ex: thread.sleep(2000) - will wait for 2 seconds

2. Waits for only once at the command given at sleep.