how can you save highscores using this

using UnityEngine;
using UnityEngine.UI;
using System.Collections;

public class ScoreManager : MonoBehaviour
{
public static int score; // The player’s score.

public Text scoretext;                      // Reference to the Text component.

void Start()
{
	PlayerPrefs.GetInt ("ScorePref");
	score = PlayerPrefs.GetInt ("ScorePref");
}

void Awake ()
{
	// Set up the reference.
	scoretext = GetComponent <Text> ();
	
	// Reset the score.
	score = 0;
}


void Update ()
{
	if(Input.GetMouseButtonDown(0))
	{
		PlayerPrefs.DeleteAll();
	    score = 0;
	}
	  
	scoretext.text = "Score: " + score;
	PlayerPrefs.SetInt ("ScorePref", score);
}

}

Yes you can use player preferences to save high scores, i have done it myself. I have not looked at your code it detail but i presume your logic is right. I hope that solves your query.

it has thanks