How to replace (onclick) with enter key

Question

  <label id = "MessageLabel"> Message </label>
        <input id = "ComposedMessage" type = "text">
        <input id = "SendMessage" onclick="Send()" value = "Send" class = "Button" type = "submit">

I have this code above,and I want to be able to click submit as well as use the enter key to submit text. How would I do that? I'm fairly new to JS and beginning HTML.