Execute same script for different events

Hi,
How to execute the same script in two different events ?
For exemple : when I write a long script in “Client Scripts ->Table-Specific → Add/Copy page” and I want the same script to run in “Client Scripts ->Table-Specific → Edit page”. I don’t to repeat (copy/paste) my code. How can I call script for Add/Copy page from Edit page ?
Thanks

You may use Client side events instead.