Slider.value

public float value ;

Description

The current value of the slider.

using UnityEngine;
using System.Collections;
using UnityEngine.UI; // Required when Using UI elements.

public class Example : MonoBehaviour
{
    public Slider mainSlider;

    //Invoked when a submit button is clicked.
    public void SubmitSliderSetting()
    {
        //Displays the value of the slider in the console.
        Debug.Log(mainSlider.value);
    }
}