<div id="menu">
<input type="text"><br>
<input name="butt" type="button" onclick="NewTeg()" value="Добавить кнопку">
</div>
<script type="text/javascript">
function NewTeg(){
var Div=document.getElementById('menu');
var button_2=Div.getElementsByTagName('input')[1];
alert("button_2.value=>"+button_2.value)
Div.removeChild(button_2)
}
</script>