代码：
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>js限制textarea输入框输入字数 - www.plcxue.com</title>
<script language="javascript">
<!--
function checktext(text)
{
allValid = true;
for (i = 0; i < text.length; i++)
{
if (text.charAt(i) != " ")
{
allValid = false;
break;
}
}
return allValid;
}
function gbcount(message,total,used,remain)
{
var max;
max = total.value;
if (message.value.length > max) {
message.value = message.value.substring(0,max);
used.value = max;
remain.value = 0;
<!-- alert("留言不能超过 200 个字!");-->
alert("不能超过"+total.value+"个字!");
}
else {
used.value = message.value.length;
remain.value = max - used.value;
}
}
-->
</script>
<style type="text/css">
<!--
* {padding:0; margin:0;}
body, html {text-align:left; font-size:12px; line-height:150%; margin:0 auto; background:#fff; padding-top:20px;}
fieldset {padding:10px; width:550px; margin:0 auto;}
legend {font-size:14px; font-weight:bold;}
.inputtext {border:none; background:#fff;}
-->
</style>
</head>
<body>
<form action="SaveData.asp" method="post" >
<fieldset><legend>请输入内容</legend>
<textarea name="Memo" rows="10" wrap=PHYSICAL cols="75" onKeyDown="gbcount(this.form.Memo,this.form.total,this.form.used,this.form.remain);" onKeyUp="gbcount(this.form.Memo,this.form.total,this.form.used,this.form.remain);"></textarea>
<p>最多字数：
<input disabled maxLength="4" name="total" size="3" value="10" class="inputtext">
已用字数：
<input disabled maxLength="4" name="used" size="3" value="0" class="inputtext">
剩余字数：
<input disabled maxLength="4" name="remain" size="3" value="10" class="inputtext"></td>
</p>
</fieldset>
</form>
<input type="text" maxLength="100" name="test" size="10" >
</body>
</html>