why does this work?

input with id, 'here' is accessed with dot notation

HTML

<input id="here" readonly>
<input type="button" id="btn" value="Click">

JavaScript

$(document).ready(function() {
  $('#btn').on('click', function() {
  	// why does this dot notation work for id?
    here.value = 'you clicked on the button';
    // should be:
    // $('#here').val('you clicked on the button');
  });
});