Version: 2017.3
public UI.Button.ButtonClickedEvent onClick ;

Description

UnityEvent that is triggered when the button is pressed.

Note: Triggered on MouseUp after MouseDown on the same object.

using UnityEngine;
using UnityEngine.UI;
using System.Collections;

public class ClickExample : MonoBehaviour { public Button yourButton;

void Start() { Button btn = yourButton.GetComponent<Button>(); btn.onClick.AddListener(TaskOnClick); }

void TaskOnClick() { Debug.Log("You have clicked the button!"); } }