GUI healthbar

Hi there. I need help from anyone. Im new in unity i'm doing my healthbar. I'm using texture. Im not sure how am i gonna declare the texture cause i keep getting error unity texture 2d cannot convert to int. all i wanted was my healthbar to change its width as the healthcount is changing too.

here's my script. hope someone can help me guys.

 var maxHealth = 100;
 var currHealth;
 var damage :int = 10;
 var myHealthbar:Texture2D ;// green
 var healthbarWidth :int;
 var myhp;
 function Start () {
 healthbarWidth = 100;
  //var myhp=Instantiate(myHealthbar, transform.position, transform.rotation);
 }
 
 function Update()
     {
       if (Input.GetKeyDown(KeyCode.F8)) 
       ApplyDamage();
      
     }
 
 function ApplyDamage ()
     {
 
     maxHealth = maxHealth - damage ;
     healthbarWidth = maxHealth;
     healthbarWidth = myHealthbar;//maxHealth * 100;
     GUI.Box( Rect (10,10, 100,50), myHealthbar);
     print(maxHealth);
 
     if (maxHealth == 0)
     {
     die();
     }
     }
 
 
 function die () 
     {
     yield WaitForSeconds(2.0);
     Destroy(gameObject);
     }

thanks in advance:)