RequireJS load module mechanism

## app.js
require(['main'], function(main) {
    main.hello();
});

## index.html
<!DOCTYPE html>
<html>
<head>
    <title>Hello RequireJS boilerplate</title>
    <meta charset="utf-8" />
</head>
<body>
    <h1>RequireJS load module mechanism</h1>
    <p>Open your console</p>
    <ol>
        <li>require module: mod1</li>
        <li>require module: mod2</li>
        <li>require module: main</li>
        <li>hello mod1</li>
        <li>hello mod2</li>
        <li>hello main</li>
    </ol>
    <h2>Conclusion</h2>
    <p>RequireJS execute module as <strong>SOON</strong> as possible(RequireJS会先尽早地执行[依赖]模块, 相当于所有的require都被提前了, 而且模块执行的顺序也不一定100%就是先mod1再mod2)</p>
    <p>So DO NOT trust your code!(因此你看到执行顺序和你预想的完全不一样! 颤抖吧~ RequireJS!)</p>
    <strong>Orz!</strong>
    <p>Test with RequireJS 2.1.6</p>
    <script data-main="js/app.js" src="lib/require.js"></script>
</body>
</html>

## main.js
define(function(require, exports, module) {
    console.log('require module: main');

    var mod1 = require('mod1');
    mod1.hello();
    var mod2 = require('mod2');
    mod2.hello();

    return {
        hello: function() {
            console.log('hello main');
        }
    };
});

## mod1.js
define(function(require, exports, module) {
    console.log('require module: mod1');

    return {
        hello: function() {
            console.log("hello mod1");
        }
    };
});

## mod2.js
define(function(require, exports, module) {
    console.log('require module: mod2');

    return {
        hello: function() {
            console.log("hello mod2");
        }
    };
});