多行文本框限制输入字符长度(两种方法)

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 >

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 >
    
    
     < SCRIPT  LANGUAGE ="JavaScript" >










     SCRIPT >
    
HEAD >
< BODY >
    
     < 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 >