第一种:
<textarea onkeyup="checkLen(this)"></textarea>
<div>您还可以输入 <span id="count">200</span> 个文字</div>
<script type="text/javascript">
function checkLen(obj) {
var maxChars = 200;//最多字符数
if (obj.value.length > maxChars) obj.value = obj.value.substring(0,maxChars);
var curr = maxChars - obj.value.length;
document.getElementByIdx_x("count").innerHTML = curr.toString();
}
</script>
第二种:
<textarea onpropertychange="if(value.length>100) value=value.substr(0,100)" class="smallArea" cols="60" name="txta" rows="8"></textarea>
第三种:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<meta name="robots" content="all" />
<meta name="author" content=",混蛋鱼" />
<meta name="Copyright" content="混蛋鱼VS男人猫 CopyRight 2007" />
<meta name="keywords" content="JS,Blog,ASP,designing,with,web,standards,xhtml,css,graphic,design,layout,usability,accessibility,w3c,w3,w3cn" /><meta name="description" content="JS限制textarea输入框输入字数" />
<title>JS限制textarea输入框输入字数</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!");
}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" onSubmit="return datacheck();">
<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="200" 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="200" class="inputtext">
</p>
</fieldset>
</form>
</body>
</html>
http://jingyan.baidu.com/article/76a7e409b8cf30fc3b6e15e2.html