Unity Script Reference:

static function HorizontalSlider(position: Rect, value: float, leftValue: float, rightValue: float): float;

static function HorizontalSlider(position: Rect, value: float, leftValue: float, rightValue: float, slider: GUIStyle, thumb: GUIStyle): float;

Parameters

position	Rectangle on the screen to use for the slider.
value	The value the slider shows. This determines the position of the draggable thumb.
leftValue	The value at the left end of the slider.
rightValue	The value at the right end of the slider.
slider	The GUIStyle to use for displaying the dragging area. If left out, the `horizontalSlider` style from the current GUISkin is used.
thumb	The GUIStyle to use for displaying draggable thumb. If left out, the `horizontalSliderThumb` style from the current GUISkin is used.

Returns
float The value that has been set by the user.

Description

A horizontal slider the user can drag to change a value between a min and a max.

	// Draws a horizontal slider control that goes from 0 to 10.
	var hSliderValue : float = 0.0;
	
	function OnGUI () {
		hSliderValue = GUI.HorizontalSlider (Rect (25, 25, 100, 30), hSliderValue, 0.0, 10.0);
	}

using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    public float hSliderValue = 0.0F;
    void OnGUI() {
        hSliderValue = GUI.HorizontalSlider(new Rect(25, 25, 100, 30), hSliderValue, 0.0F, 10.0F);
    }
}

import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	public hSliderValue as float = 0.0F

	def OnGUI() as void:
		hSliderValue = GUI.HorizontalSlider(Rect(25, 25, 100, 30), hSliderValue, 0.0F, 10.0F)