Health Regeneration

I have a damage receiver script and in it, I wrote a script to regenerate health:

 #pragma strict
 
 var hitPoints = 100.0;
 var regen = 10; 
 var detonationDelay = 0.0; 
 var explosion : GameObject; 
 var deadReplacement : Rigidbody;
 
 function Update() {
     if(hitPoints <= 100) {
         hitPoints += regen * Time.deltaTime;
     }
 }

The function update of course being the regeneration part. Well it's not working. Here's the whole script:

 #pragma strict
 
 var hitPoints = 100.0;
 var regen = 10; 
 var detonationDelay = 0.0; 
 var explosion : GameObject; 
 var deadReplacement : Rigidbody;
 
 function Update() {
     if(hitPoints <= 100) {
         hitPoints += regen * Time.deltaTime;
     }
 }
 
 function ApplyDamage (damage : float) { 
 
 hitPoints -= damage;
 if (hitPoints <= 0.0) {
    
     var emitter : ParticleEmitter = GetComponentInChildren(ParticleEmitter);
     if (emitter)
         emitter.emit = true;
 
     Invoke("DelayedDetonate", detonationDelay);
 }
 }
 
 function DelayedDetonate () { BroadcastMessage ("Detonate"); }
 
 function Detonate () {
      
 if (explosion)
     Instantiate (explosion, transform.position, transform.rotation);
 
 
 if (deadReplacement) {
     var dead : Rigidbody = Instantiate(deadReplacement, transform.position, transform.rotation);
 
     
     dead.rigidbody.velocity = rigidbody.velocity;
     dead.angularVelocity = rigidbody.angularVelocity;
 }
 
 
 var emitter : ParticleEmitter = GetComponentInChildren(ParticleEmitter);
 if (emitter) {
     emitter.emit = false;
     emitter.transform.parent = null;
 }
 Destroy (gameObject);
 }

I'm not sure why it's not working. The regen should be adding to it every second by ten, but, nothing is happening. Why is this?