# Functions <small>(are awesome)</small>

Functions are mini-programs (within your big program) that you
give a name to. Then you can run them again & again, just by
"calling" them.


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<#print-badge-context


## Creating & Calling a Function

Let's make a function called `shinerdog` that howls
annoyingly every time we call it.

Type this into the prompt on the right:
<small>_and press enter_</small>

```javascript.not-runnable
function shinerdog() {
    alert("WOOOOooooOOoOOF!")
}
```

Nothing happened! That's OK. All that did is tell the computer,
"hey, I'm making this function called `shinerdog`".

Now run the function by calling it:

```javascript
shinerdog()
```

Damn dog is always howling at people :)

Let's make another function to tell him to stop:

```javascript
function shut_up_shiner() {
    alert("SHINER! HUSH!")
}
```

Tell him what's up:

```javascript
shinerdog()
shut_up_shiner()
```

<small>*shiner slinks away & curls up in a chair*</small>

> ### A less annoying `alert()`
> `alert()` is just a function like any other, but it's one
> that comes bulit-into the web browser. We can call `alert()`
> anytime we want to display something, but that popup window
> is annoying.
> 
> Instead -- from here on out -- we'll use its less-annoying
> cousin, `console.log()`, which will display its results
> in your prompt, instead of in an annoying popup window.


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## Inputs /(make functions dance)/

That's the basics[*][shiner] of creating and calling a function, but so far
our functions are of limited usefulness. A function that just does
the same thing over & over is kind of pointless [[shrug]]

Let's do something a little more interesting.
Pretend we're organizing a conference, and we want to make a computer
program that will print out name bages for each of our guests.

Based on what we know so far, we could write a function that prints
`Hello, my name is __________` -- but that's no good.
This is a fancy conference, so our badges need names, dammit!
Somehow, we have to tell our function the name of each guest,
so it can print out `Hello, my name is Mike Jones` instead.

That's where __inputs__ come in. A function can take an input,
and then use that input in its code.

This functiont akes an input called `guest_name`. Fill in the blank:

```javascript
function print_badge(guest_name) {
    console.log("Hello, my name is " + [[____________]])
}
```

Then when you call it, you "pass" it a value for its innput:

```javascript
print_badge("Mike Jones")
```



```javascript.hidden#print-badge-context
function shiner() {
    console.log("I AM A DOG")
}
```


[shiner]: http://google.com "Shiner is a dog"