"In the previous tutorial we've built the html structure for our chatbot and now it's jQuery's time. In this tutorial we are going to make the "send on enter" feature, which will be a checkbox and when it's checked the message can be sent by pressing the Enter key on the keyboard. When it's not, you can create new lines by pressing Enter and send the message by clicking the button..."
http://www.mybringback.com/?p=13727