<%@ Page Language="C#" AutoEventWireup="true" CodeFile="text_area.aspx.cs" Inherits="text_area" %>
<!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 runat="server">
<title>纯JS限制文本框字数</title>
<script type="text/javascript">
window.onload = function() {
document.getElementById("txtContent").onkeyup = function() {
var len = this.value.length;
var tmp = 10 - len;
if (tmp <= 0) {
this.value = this.value.substring(0, 10);
document.getElementById("mes").innerHTML = "您还可以输入 0 个字符";
} else {
document.getElementById("mes").innerHTML = "您还可以输入 " + tmp + " 个字符";
}
}
}
</script>
</head>
<body>
<form id="form1" runat="server">
<asp:TextBox ID="txtContent" TextMode="MultiLine" runat="server" Height="190px" Width="439px"></asp:TextBox>
<div id="mes">
您还可以输入 10 个字符
</div>
</form>
</body>
</html>