Input.GetButton

static function GetButton (buttonName : String) : boolean

Description

Returns true while the virtual button identified by buttonName is held down.

Think auto fire - this will return true as long as the button is held down.

Use this only when implementing action like events IE: shooting a weapon.
Use Input.GetAxis for any kind of movement behaviour.

JavaScript
// Instantiates a projectile every 0.5 seconds,
// if the Fire1 button (default is Ctrl) is pressed.

var projectile : GameObject;
var fireRate : float = 0.5;
private var nextFire : float = 0.0;
function Update () {
if (Input.GetButton ("Fire1") && Time.time > nextFire) {
nextFire = Time.time + fireRate;
var clone : GameObject =
Instantiate(projectile, transform.position, transform.rotation) as GameObject;
}
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
public GameObject projectile;
public float fireRate = 0.5F;
private float nextFire = 0.0F;
void Update() {
if (Input.GetButton("Fire1") && Time.time > nextFire) {
nextFire = Time.time + fireRate;
GameObject clone = Instantiate(projectile, transform.position, transform.rotation) as GameObject as GameObject;
}
}
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

public projectile as GameObject

public fireRate as single = 0.5F

private nextFire as single = 0.0F

def Update():
if Input.GetButton('Fire1') and (Time.time > nextFire):
nextFire = (Time.time + fireRate)
clone as GameObject = (Instantiate(projectile, transform.position, transform.rotation) as GameObject)