Random screen position Unity

RandomScreenPos.cs

using UnityEngine;
using System.Collections;

public class RandomScreenPos : MonoBehaviour {

	void Update() {
		float x = Random.Range(0f, Screen.width);
		float y = Random.Range(0f, Screen.height);
		float z = Random.Range(Camera.main.nearClipPlane, Camera.main.farClipPlane);
		transform.position = Camera.main.ScreenToWorldPoint(new Vector3(x, y, z));
	}

}