In 'git bash'
mkdir behave && cd behave
git init
git pull https://github.com/jakiestfu/Behave.js.git master
Copy behave.js, into your local project.
<script type='text/javascript' src='js/behave.js'></script>
<script type='text/javascript'>
var editor = new Behave({
textarea: document.getElementById('myTextarea')
});
</script>
<body>
<div id='myTextarea'></div>
</body>
Bingo => myTextarea is now behavified.