The $('#myInput') is the reference to the combogrid object. You can wrap the combogrid with a <span> element and then access it.
<id="mySpan" span>
<input id="myInput" class="easyui-combogrid" ...>
</span>
To show or hide the combogrid, call this code:
$('#mySpan').show();
// $('#mySpan').hide();