I have created a javascript file with some utility functions. How do I "include" to those functions from another javascript file? Also if I create a global variable inside one of my javascript files, can the utility functions see that variable if they are called?

Simply include all .js file's that you need in your document.
Here's simple demo to clear things out:
saying i have 3 .js files:

var varThree = varTwo; 
// varThree variable is not accessible to two.js and one.js
// But varThree can access variables from the two other .js


var varTwo = varOne; // this varible is not accessible to one.js but accessible to three.js


var varOne = "Hello World"; 
// This variable is accesible to all other .js

// all your .js file's must be in an ascending form when you load them in your document's to access each variables.

Now let's see the output:

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7" />
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta http-equiv="Content-Style-Type" content="text/css" />
<meta http-equiv="Content-Script-Type" content="text/javascript" />
<title>Test Page</title>
<script type="text/javascript" src="one.js"></script>
<script type="text/javascript" src="two.js"></script>
<script type="text/javascript" src="three.js"></script>
<script type="text/javascript">
window.onload = function() {
alert( varThree );
<div id="content">


Thanks for the clear illustration. It works fine and was helpful in helping me start to get a feel for javascript (compared to compiled languages for example).