ASP.Net - Validate form using css in C#.Net

Output:

Html Code:

<!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 id="Head1" runat="server">

    <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js" type="text/javascript"></script>

    <title>Show error message using css</title>

</head>

<body>

    <form id="form1" runat="server">

    <div class="field-box control-group">

        <label class="span4">

            Note:</label>

        <textarea name="Text1" class="span3" cols="40" rows="5" id="txt_Note" runat="server"></textarea>

        <span style="color:red;display: none;">Please enter the note..</span>

    </div>

    <div class="field-box control-group">

        <label class="span4">

            Tag:</label>

        <input class="span3" id="txt_tag" type="text" runat="server" />

        <span style="color:red;display: none;">Please enter the tag..</span>

    </div>

     <div class="field-box control-group">

        <label id="lblstatus"></label>

        </div>

    <div class="span6 field-box actions">

        <input type="button" id="btnClose" class="btn-glow primary" value="Close" >

        </input>

        <input type="button" class="btn-glow primary" id="btnSubmit" value="Add New" onclick="return fnValidate();"/>

    </div>

    </form>

    <script type="text/javascript">

        function fnValidate() {

            if ($('#txt_Note').val() == "") {

                $('#txt_Note').css("border", "1px solid red");

                $('#txt_Note').next('span').show();

                return false;

            }

            else {

                $('#txt_Note').css("border", "1px solid #000");

                $('#txt_Note').next('span').hide();

            }

            if ($('#txt_tag').val() == "") {

                $('#txt_tag').css("border", "1px solid red");

                $('#txt_tag').next('span').show();

                return false;

            }

            else {

                $('#txt_tag').css("border", "1px solid #000");

                $('#txt_tag').next('span').hide();

            }

            $('#lblstatus').text('Success').css('color','green');

        }

    </script>

</body>

</html>