<html><head> <meta http-equiv="Content-Type" content="text/html; charset=gb2312"> <title>新建网页 1</title> </head> <script language="javascript"> function onCheck(){ var textar= document.forms[0].textar.value; var i; var len; for(i=0,len=0;i<textar.length;i++){
<textarea name="infodetail" cols="50" wrap="PHYSICAL" rows="10"></textarea>
</td>
说说怎么判断?
<textarea name="mytxta" onkeypress="if(this.innerText.length >=5) {alert('只能输入5个字符');return(false);}"></textarea>
<textarea name="infodetail" cols="50" wrap="PHYSICAL" rows="10"></textarea>
</td>这个在form中定义后,可以在JavaScript中进行判断。 var INFODETAIL
<textarea name="infodetail" cols="50" wrap="PHYSICAL" rows="10"></textarea>
</td>
在JavaScript中写个函数进行检查。
……
var INFODETAIL = document.forms[0].infodetail;
通过判断INFODETAIL 的value来实现。
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<style type="text/css">
<!--
body {
margin-left: 0px;
margin-top: 0px;
}
.edit {
clear: right;
color: #0066FF;
border: 1px solid #FFCC00;
}
.button {
clear: right;
border: 1px solid #999999;
background-color: #FFFFFF;
}
.font12 {
font-size: 12px;
text-decoration: none;
}
.style2 {font-size: 12px; text-decoration: none; color: #FF0000; }
-->
</style></head>
<SCRIPT LANGUAGE="JavaScript">
<!-- Begin
maxLen = 66; // max number of characters allowedfunction checkMaxInput(form) {
if (form.answer.value.length > maxLen) // if too long.... trim it!
form.answer.value = form.answer.value.substring(0, maxLen);
// otherwise, update 'characters left' counter
else form.remLen.value = maxLen - form.answer.value.length;
}
// End -->
</script>
<body>
<form name="form1" method="post" action="reply.asp">
<table width="329" height="90" border="0" align="center" cellpadding="1" cellspacing="2">
<tr>
<td width="445" height="57"><textarea name='answer' cols='50' rows='3' wrap='VIRTUAL' class="edit" id="answer" onKeyDown="checkMaxInput(this.form)" onKeyUp="checkMaxInput(this.form)" ></textarea>
<input name="remLen" type="text" class="edit" value="66" size="3" maxlength="3" readonly>
<span class="style2">字符数 </span></td>
</tr>
<tr>
<td height="27" align="center"><input name="Submit" type="submit" class="button" value="发 送" >
<input name="Submit2" type="button" class="button" value="关 闭" onclick="window.close()"></td>
</tr>
</table>
</form>
</body>
</html>
<script language='javascript'>
String.prototype.lenB = function(){return this.replace(/[^\x00-\xff]/g,"**").length;}
</script>
中文按两个字符计算:<br>
<textarea name="mytxta" onpaste="if ((window.clipboardData.getData('Text').lenB()+this.innerText.lenB())>=5){alert('只能输入5个字符!');return(false);}"
onkeypress="if(this.innerText.length >=5) {alert('只能输入5个字符');return(false);}"></textarea>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>新建网页 1</title>
</head>
<script language="javascript">
function onCheck(){
var textar= document.forms[0].textar.value;
var i;
var len;
for(i=0,len=0;i<textar.length;i++){
if(textar.charCodeAt(i)<128){
len++;
}
else{
len=len+2;
} }
if(len>5) {
alert("输入的信息超长。");
return false ;
}
return true;
}
</script>
<body><form method="POST" action="--WEBBOT-SELF--">
<!--webbot bot="SaveResults" U-File="file:///C:/Inetpub/wwwroot/_private/form_results.csv" S-Format="TEXT/CSV" S-Label-Fields="TRUE" -->
<p><textarea name="textar" rows="2" name="S1" cols="20" onBlur="onCheck()"></textarea></p>
</form></body>
</html>
改为<p><textarea name="textar" rows="2" cols="20" onBlur="onCheck()"></textarea></p>