GUI.changed

Description

Returns true if any controls changed the value of the input data.

// Draws a text field and when it gets modified prints a message
using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour
{
    public string stringToEdit = "Modify me.";

    void OnGUI()
    {
        // Make a text field that modifies stringToEdit.
        stringToEdit = GUI.TextField(new Rect(10, 10, 200, 20), stringToEdit, 25);

        if (GUI.changed)
        {
            Debug.Log("Text field has changed.");
        }
    }
}