Let’s go back to the view and see how the behavior is defined for adding lines to the chat.

<form class="lift:form.ajax"> defines an input form and the form.ajax snippet turns a form into an Ajax (see ↓) form that will be submitted back to the server without causing a full page load.

Next, we define the input form element: <input class="lift:ChatIn" id="chat_in"/>. It’s a plain old input form, but we’ve told Lift to modify the <input>’s behavior by calling the ChatIn snippet.