多行文本框限制输入字符长度(两种方法)
今天发现textbox设置为multiline后，设置maxlength不起作用，网上找了两种解决办法：
<HTML>
<HEAD>
<title>WebForm6</title>
<meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
<meta name="CODE_LANGUAGE" Content="C#">
<meta name="vs_defaultClientScript" content="JavaScript">
<meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">
<script language="javascript">
function isOver(sText,len)
{
var intlen=sText.value.length;
if (intlen>len)
{
alert("The content length must Less than or Equal "+len);
sText.focus();
sText.select();
}
}
</script>
</HEAD>
<body MS_POSITIONING="GridLayout">
<form id="Form1" method="post" runat="server">
<asp:TextBox id="txtName" style="Z-INDEX: 102; LEFT: 200px; POSITION: absolute; TOP: 104px" runat="server"
TextMode="MultiLine" Height="112px" Width="271px"></asp:TextBox>
</form>
</body>
</HTML>2.cs代码
private void Page_Load(object sender, System.EventArgs e)
{
this.txtName.Attributes.Add("onblur","isOver(this,1000);");
}方法二：限制用户继续输入
<HEAD>
<!-- TWO STEPS TO INSTALL LIMIT TEXTAREA:
1. Copy the coding into the HEAD of your HTML document
2. Add the last code into the BODY of your HTML document -->
<!-- STEP ONE: Paste this code into the HEAD of your HTML document -->
<SCRIPT LANGUAGE="JavaScript">
<!-- Original: Ronnie T. Moore -->
<!-- Web Site: The JavaScript Source -->
<!-- Dynamic 'fix' by: Nannette Thacker -->
<!-- Web Site: http://www.shiningstar.net -->
<!-- This script and many more are available free online at -->
<!-- The JavaScript Source!! http://javascript.internet.com -->
<!-- Begin
function textCounter(field, countfield, maxlimit) {
if (field.value.length > maxlimit) // if too long
trim it!
field.value = field.value.substring(0, maxlimit);
// otherwise, update 'characters left' counter
else
countfield.value = maxlimit - field.value.length;
}
// End -->
</SCRIPT>
<!-- STEP TWO: Copy this code into the BODY of your HTML document -->
</HEAD>
<BODY>
<!-- textCounter() parameters are: text field, the count field, max length -->
<center>
<form name="myform" action="YOUR-SCRIPT.CGI">
<font size="1" face="arial, helvetica, sans-serif">( You may enter up to 125
characters. )<br>
<textarea name="message" wrap="physical" cols="28" rows="4" onKeyDown="textCounter(this.form.message,this.form.remLen,125);"
onKeyUp="textCounter(this.form.message,this.form.remLen,125);"></textarea>
<br>
<input readonly type="text" name="remLen" size="3" maxlength="3" value="125"> characters
left</font>
</form>
</center>
<p><center>
<font face="arial, helvetica" SIZE="-2">Free JavaScripts provided<br>
by <a href="http://javascriptsource.com">The JavaScript Source</a></font>
</center>
</BODY>
方法一：弹出对话框提示
1.html代码
<HTML> <HEAD> <title>WebForm6</title> <meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1"> <meta name="CODE_LANGUAGE" Content="C#"> <meta name="vs_defaultClientScript" content="JavaScript"> <meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5"> <script language="javascript"> 
function isOver(sText,len) {
var intlen=sText.value.length; if (intlen>len) { alert("The content length must Less than or Equal "+len); sText.focus(); sText.select(); } } </script> </HEAD> <body MS_POSITIONING="GridLayout"> <form id="Form1" method="post" runat="server"> <asp:TextBox id="txtName" style="Z-INDEX: 102; LEFT: 200px; POSITION: absolute; TOP: 104px" runat="server" TextMode="MultiLine" Height="112px" Width="271px"></asp:TextBox> </form> </body></HTML>private void Page_Load(object sender, System.EventArgs e) { this.txtName.Attributes.Add("onblur","isOver(this,1000);"); }<HEAD> <!-- TWO STEPS TO INSTALL LIMIT TEXTAREA: 1. Copy the coding into the HEAD of your HTML document 2. Add the last code into the BODY of your HTML document --> <!-- STEP ONE: Paste this code into the HEAD of your HTML document --> <SCRIPT LANGUAGE="JavaScript"><!-- Original: Ronnie T. Moore --><!-- Web Site: The JavaScript Source --><!-- Dynamic 'fix' by: Nannette Thacker --><!-- Web Site: http://www.shiningstar.net --><!-- This script and many more are available free online at --><!-- The JavaScript Source!! http://javascript.internet.com --><!-- Beginfunction textCounter(field, countfield, maxlimit) {if (field.value.length > maxlimit) // if too longtrim it!field.value = field.value.substring(0, maxlimit);// otherwise, update 'characters left' counterelse countfield.value = maxlimit - field.value.length;}// End --> </SCRIPT> <!-- STEP TWO: Copy this code into the BODY of your HTML document --></HEAD><BODY> <!-- textCounter() parameters are: text field, the count field, max length --> <center> <form name="myform" action="YOUR-SCRIPT.CGI"> <font size="1" face="arial, helvetica, sans-serif">( You may enter up to 125 characters. )<br> <textarea name="message" wrap="physical" cols="28" rows="4" onKeyDown="textCounter(this.form.message,this.form.remLen,125);" onKeyUp="textCounter(this.form.message,this.form.remLen,125);"></textarea> <br> <input readonly type="text" name="remLen" size="3" maxlength="3" value="125"> characters left</font> </form> </center> <p><center> <font face="arial, helvetica" SIZE="-2">Free JavaScripts provided<br> by <a href="http://javascriptsource.com">The JavaScript Source</a></font> </center></BODY>
