Web automation FireEvents

How to trigger Onchange/Onclick events in the Webpage .

Also how to select from the list of the dropdown which is generated by the script after running the script

example for 2nd one :



can you please give me a example as
CLick Trigger :Monitors click events on a specified UI element. Can only be used inside a Monitor Events activity.

I want to run the script in webpage which is running with change in text in text box of webpage and then generates a list of values in the drop down