限制多行文本框输入字符长度(两种方法)
原文:小山 http://www.cnblogs.com/singlepine/archive/2005/10/31/265807.html
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 long
trim 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>
