How come my player animation won't play?

I have a model and I already have the walk and Idle animation to play but somehow I can never get the "Jump" to play. I really can't figure why?

I used tried triggers but still no good.

here is my code on my model called "AnimatePlayer":

 #pragma strict
 
 var body : Transform; //Tranform the armature of the player model
 
 var mousexThreshold = 0.2; //Number of units for the mouse to move on x-axis
 
 //Settings for the Upper Body rotation
 var sensitivityY = 15F;
 var minimumY = -60F;
 var maximumY = 60F;
 var rotationY = 0F;
 var jumpBool : boolean;
 
 
     function Start()
      {
          //set animation Wrap Mode for the attack to "Once"
          animation["Jump"].wrapMode = WrapMode.Once;
      }
 
 function Update () {
 
 
 if( transform.rotation.eulerAngles.y == 270 ) { // Left rotation
 
 if(Input.GetAxis("Horizontal") > 0) //Walk Backwards
 {
 animation["Walk"].speed = -2;
 animation.Play("Walk");
 }
 
 else if(Input.GetAxis("Horizontal") < 0) //Walk Forward
 {
 animation["Walk"].speed = 2;
 animation.Play("Walk");
 }
 
 else if(Input.GetAxis("Horizontal") == 0)
 {
 animation.Play("Idle");
 }
 }
 
 
 if( transform.rotation.eulerAngles.y == 90.00001 ) { // Right rotation
 
 if(Input.GetAxis("Horizontal") > 0) //Walk Forward
 {
 animation["Walk"].speed = 2;
 animation.Play("Walk");
 }
 
 else if(Input.GetAxis("Horizontal") < 0) //Walk Backwards
 {
 animation["Walk"].speed = -2;
 animation.Play("Walk");
 }
 
 else if(Input.GetAxis("Horizontal") == 0) //Return to standing posture
 {
 animation.Play("Idle");
 }
 }
 
     // Transform the rotation of the player when mouse moves on the x-axis
      var mousex : float = Input.GetAxis ("Mouse X");
      
      if (mousex > mousexThreshold) //Player faces right
      {
    transform.forward = new Vector3(1f, 0f, 0f);
 
      }
      
      
      else if (mousex < -mousexThreshold) //Player faces left
      {
    transform.forward = new Vector3(-1f, 0f, 0f);
 
       }
 
 }
 
 
 function LateUpdate(){
 
     // will make the upper body of the model to be rotatable along the y-axis
 
    rotationY += Input.GetAxis("Mouse Y") * sensitivityY;
             rotationY = Mathf.Clamp (rotationY, minimumY, maximumY);
  
             body.transform.localEulerAngles = new Vector3(0, rotationY, 0); 
           
 }
 
 function OnTriggerEnter(other : Collider){
 if(other.tag == "Ground"){
 animation.Play("Jump");
 }else if(other.tag == "Platform"){
 animation.Play("Jump"); 
 }
 }
 
 function OnTriggerExit(other : Collider){
 if(other.tag == "Ground"){
 animation.Play("Idle");
 }else if(other.tag == "Platform"){
 animation.Play("Idle");
 }
 }

As you can see, I have a trigger to play the "Jump" animation but still nothing. Is it because I have a lot of animations playing all at once?