<input type=text name='tempinput' id='tempinput'>
<script>
$('#tempinput").attr("readonly",true); //설정
$('#tempinput").attr("readonly",false); //해제
</script>
<input type=text name='tempinput' id='tempinput'>
<script>
$('#tempinput").attr("readonly",true); //설정
$('#tempinput").attr("readonly",false); //해제
</script>