append jquery mobile textarea not expendable in multiline input

append jquery mobile textarea not expendable in multiline input

Im just added jQueryMobile on my project, and the auto expending textarea
is rock. However, when i change my method, i append a textarea into a div,
and the textarea not expending anymore. Do i miss out something or other
code can help to solve this?
<div id="text"></div>
Javascript
$("#text").append('<div data-role="fieldcontain"><textarea id="msg_input"
cols="30" rows="1" name="textarea"></textarea></div>');
The textarea is display out, but not growing on next line.
Any help?
Steven