how to access the selectionRange using the onselect event object in textarea

Question

I am working on a project where I will be getting all the events that have occurred in a textarea and give a replay of the events. To fulfill this objective, I am collecting all the events that have occured in a textarea. I am storing the events in an object array containing the event and timestamp. Now for onselect events, how do i get the selectionRange or some other equivalent so that i can reproduce text selection.