chat.js

define( ['vendor/jquery.js'], function( $ ){

    var chat = function( el ){

		// just in case this is run before DOM is loaded
		$(function(){

			var $el = $( el );
			var $message_form = $el.find('form');
			var $new_message = $el.find(':input.message');
			var $messages = $el.find('.messages');

			// add a message to the messages element
			var addMessage = function( message ){
				var $message = $('<p></p>');
				$message.text( message );
				$messages.prepend( $message );
			};

			// handle message submission event
			var submitMessage = function( e ){
				e.preventDefault();
				var message = $.trim( $new_message.val() );
				if( message ){
					addMessage( message );
					$new_message.val('');
				}
			};

			$message_form.on( 'submit', submitMessage );

		});

	};

	return chat;

});