GUILayer.HitTest
HitTest(screenPosition: Vector3): GUIElement;
GUIElement HitTest(Vector3 screenPosition);
def HitTest(screenPosition as Vector3) as GUIElement
Description

Get the GUI element at a specific screen position.

Returns the GUIElement at a specific point on screen. If screenPosition is inside some GUIElement, that element is returned. Returns null if the position is not inside any GUI element. GUI elements that belong to Ignore Raycast layer will be ignored, as if they would not exist.

screenPosition is measured in screen coordinates, like the values returned by Input.mousePosition property.

Note: GUILayer.HitTest only finds old-school GUI components (made up of the classes GUIElement, GUITexture, GUIText, GUILayer), and will not work with the "new" one (referred to as "UnityGUI" and made up of all the other GUIAnything classes, and the OnGUI() call).
So if you're using UnityGUI, HitTest won't find anything.

See Also: GUIElement.HitTest, Input.mousePosition.
	// Tests if the mouse is touching a GUIElement.
	// Add a GUITexture and put the mouse over it and
	// it will print the GUITexture name.
	private var test : GUILayer;
	test = Camera.main.GetComponent(GUILayer);
	function Update() {
		if(test.HitTest(Input.mousePosition) != null) {
			Debug.Log(test.HitTest(Input.mousePosition).name);
		}
	}
using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    private GUILayer test;
    void Update() {
        if (test.HitTest(Input.mousePosition) != null)
            Debug.Log(test.HitTest(Input.mousePosition).name);
        
    }
    void Example() {
        test = Camera.main.GetComponent<GUILayer>();
    }
}
import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	private test as GUILayer

	def Update() as void:
		if test.HitTest(Input.mousePosition) != null:
			Debug.Log(test.HitTest(Input.mousePosition).name)

	def Example() as void:
		test = Camera.main.GetComponent[of GUILayer]()