<body>
<form name="NomeForm" action="">
<input type="checkbox" name="NODATA" value="ON" onClick="document.NomeForm.DATA.value=''">
<input type="text" name="DATA" size="10">
</form>
</body>
</html>
<body>
<form name="NomeForm" action="">
<input type="checkbox" name="NODATA" value="ON" onClick="document.NomeForm.DATA.value=''">
<input type="text" name="DATA" size="10">
</form>
</body>
</html>