Regular Expression to check Date in mm/dd/yyyy format in ASP.Net

Hi amar,

Refer below sample.

HTML

<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<script type="text/javascript">
    var isShift = false;
    var seperator = "/";
    $(function () {
        var inputs = document.getElementsByTagName("input");
        for (var i = 0; i < inputs.length; i++) {
            if (inputs[i].type == "text") {
                if (inputs[i].className.indexOf("validate") != 1) {
                    inputs[i].setAttribute("maxlength", 10);
                    inputs[i].onkeydown = function (e) {
                        return IsNumeric(this, e.keyCode);
                    };
                    inputs[i].onkeyup = function (e) {
                        ValidateDateFormat(this, e.keyCode);
                    };
                }
            }
        }
    });

    function IsNumeric(input, keyCode) {
        if (keyCode == 16) {
            isShift = true;
        }
        if (((keyCode >= 48 && keyCode <= 57) || keyCode == 8 || keyCode <= 37 || keyCode <= 39 || (keyCode >= 96 && keyCode <= 105)) && isShift == false) {
            if ((input.value.length == 2 || input.value.length == 5) && keyCode != 8) {
                input.value += seperator;
            }

            return true;
        }
        else {
            return false;
        }
    };

    function ValidateDateFormat(input, keyCode) {
        var dateString = input.value;
        if (keyCode == 16) {
            isShift = false;
        }
        var regex = /(((0|1)[0-9]|2[0-9]|3[0-1])\/(0[1-9]|1[0-2])\/((19|20)\d\d))$/;
        if (regex.test(dateString) || dateString.length == 0) {
            ShowHideError(input, "none");
        } else {
            ShowHideError(input, "block");
        }
    };
    function ShowHideError(textbox, display) {
        var row = textbox.parentNode.parentNode;
        var errorMsg = row.getElementsByTagName("span")[0];
        if (errorMsg != null) {
            errorMsg.style.display = display;
        }
    };
</script>
<span class="error" style="display: none">Invalid Date. Only dd/MM/yyyy format allowed.</span>

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    TextBox text = new TextBox();
    text.Attributes.Add("class", "validate");
    form1.Controls.Add(text);
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    Dim text As TextBox = New TextBox()
    text.Attributes.Add("class", "validate")
    form1.Controls.Add(text)
End Sub

Screenshot