Legacy Documentation: Version 4.3.0
GUI.Button
static function Button(position: Rect, text: string): bool;
static bool Button(Rect position, string text);
static def Button(position as Rect, text as string) as bool
static function Button(position: Rect, image: Texture): bool;
static bool Button(Rect position, Texture image);
static def Button(position as Rect, image as Texture) as bool
static function Button(position: Rect, content: GUIContent): bool;
static bool Button(Rect position, GUIContent content);
static def Button(position as Rect, content as GUIContent) as bool
static function Button(position: Rect, text: string, style: GUIStyle): bool;
static bool Button(Rect position, string text, GUIStyle style);
static def Button(position as Rect, text as string, style as GUIStyle) as bool
static function Button(position: Rect, image: Texture, style: GUIStyle): bool;
static bool Button(Rect position, Texture image, GUIStyle style);
static def Button(position as Rect, image as Texture, style as GUIStyle) as bool
static function Button(position: Rect, content: GUIContent, style: GUIStyle): bool;
static bool Button(Rect position, GUIContent content, GUIStyle style);
static def Button(position as Rect, content as GUIContent, style as GUIStyle) as bool
Parameters

position Rectangle on the screen to use for the button.
text Text to display on the button.
image Texture to display on the button.
content Text, image and tooltip for this button.
style The style to use. If left out, the button style from the current GUISkin is used.
Returns
bool true when the users clicks the button.
Description

Make a single press button. The user clicks them and something happens immediately.

	// Draws 2 buttons, one with an image, and other with a text
	// And print a message when they got clicked.
	var btnTexture : Texture;
	function OnGUI() {
		if (!btnTexture) {
			Debug.LogError("Please assign a texture on the inspector");
			return;
		}
		if (GUI.Button(Rect(10,10,50,50),btnTexture))
			Debug.Log("Clicked the button with an image");
		if (GUI.Button(Rect(10,70,50,30),"Click"))
			Debug.Log("Clicked the button with text");
	}

using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    public Texture btnTexture;
    void OnGUI() {
        if (!btnTexture) {
            Debug.LogError("Please assign a texture on the inspector");
            return;
        }
        if (GUI.Button(new Rect(10, 10, 50, 50), btnTexture))
            Debug.Log("Clicked the button with an image");
        
        if (GUI.Button(new Rect(10, 70, 50, 30), "Click"))
            Debug.Log("Clicked the button with text");
        
    }
}

import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	public btnTexture as Texture

	def OnGUI() as void:
		if not btnTexture:
			Debug.LogError('Please assign a texture on the inspector')
			return
		if GUI.Button(Rect(10, 10, 50, 50), btnTexture):
			Debug.Log('Clicked the button with an image')
		if GUI.Button(Rect(10, 70, 50, 30), 'Click'):
			Debug.Log('Clicked the button with text')