transform.Translate on +y and -Y

hello guys , i want to make the cube translate on y and after 10 seconds translate on -y and still repeating it .
hoe i make it repeat every 10 seconds up and down up and down …sorry for my english

    Yspeed=2;
    


 function Update () {
    

    
    
    transform.Translate(0,0.03*Time.deltaTime*Yspeed,0);
    
    
    transform.Translate(0,-0.03*Time.deltaTime*Yspeed,0);
    }

#pragma strict

var Yspeed:float = 2;
var changeIntervalSeconds:float = 10;
var timer:float = 0;

var direction:int = 1;

function Update () 
{
	timer += Time.deltaTime;
	
	if (timer > changeIntervalSeconds)
	{
		direction = -direction;
		timer = 0;
	}
	
    transform.Translate(0, 0.03 * Time.deltaTime * Yspeed * direction,0);
}