TextArea的长度限定

限定200字以内.

<asp:TextBox ID="txtDomainUse" runat="server" TextMode="MultiLine" Rows="4"  Width="99%" onkeydown="textCounter(this,200)" onkeyup="textCounter(this,200)"></asp:TextBox>

<script type="text/javascript">
    function textCounter(field, maxlimit) {
        if (field.value.length > maxlimit)
            field.value = field.value.substring(0, maxlimit);
    }
</script>