Send message to specific game object

I’m new to programming in Unity, but I’ve been using PlayMaker visual scripting for a while.

I’m using JavaScript and I want to call a function in another script in my Project (or just run another script attached to a different game object). For example, when a player enters a trigger attached to an enemy, I want battle script that’s on the player to run. In Playmaker, you can use SendMessage, but how do you do this in UnityScript?
Thanks in advance.

I’m still learning to script properly but maybe this’ll help you out:

Unity Script Reference - SendMessage