Unity Script Reference:

static function HorizontalSlider(value: float, leftValue: float, rightValue: float, params options: GUILayoutOption[]): float;

static function HorizontalSlider(value: float, leftValue: float, rightValue: float, slider: GUIStyle, thumb: GUIStyle, params options: GUILayoutOption[]): float;

Parameters

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.
options	An optional list of layout options that specify extra layouting properties. Any values passed in here will override settings defined by the `style`.

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.

Horizontal slider in the GameView.

	var hSliderValue : float = 0.0;	function OnGUI () {
		hSliderValue = GUILayout.HorizontalSlider (hSliderValue, 0.0, 10.0);
                GUILayout.Label("This text makes just space");
	}

using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    public float hSliderValue = 0.0F;
    void OnGUI() {
        hSliderValue = GUILayout.HorizontalSlider(hSliderValue, 0.0F, 10.0F);
        GUILayout.Label("This text makes just space");
    }
}

import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	public hSliderValue as float = 0.0F

	def OnGUI() as void:
		hSliderValue = GUILayout.HorizontalSlider(hSliderValue, 0.0F, 10.0F)
		GUILayout.Label('This text makes just space')