according to w3 schools <textarea>
supports onresize
however it is not working.
http://www.w3schools.com/jsref/event_onresize.asp
browsers tried:
Chrome 25.0.1364.172
Safari 6.0.3 (7536.28.10)
Firefox 19.0
FIDDLE: http://jsfiddle.net/btevfik/5abR3/
update
as i learned my lesson not to trust w3schools 100%, i found this
https://developer.mozilla.org/en-US/docs/DOM/element.onresize
Textareas don't resize in MOST(ALL) the browsers onresize event is NOT WORKING FOR the window object in this case, you case use jQuery UI plugin:
$("idoftextarea").resizable({
resize: function() {
$("id").append("yourcode");
}
});
Reference: http://jqueryui.com/resizable/