隐藏textarea

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>无标题文档</title>
<script language="javascript">
function ShowTxt()
{
 document.getElementById("txt").style.display="block";
}
function HiddenTxt()
{
 document.getElementById("txt").style.display="none";
}
</script>
</head>

<body >

<textarea name="txt" rows="5" cols="20" style="display:none" id="txt">
</textarea>
<input type="button" value="显示" onClick="ShowTxt()" />
<input type="button" value="隐藏" onClick="HiddenTxt()" />
</body