How to validate when leaving texbox in ASP.NET using data-anotation?

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C#5.0

bootstrap

ASP.NET5

, +

Hi Team

I want to validate when leaving the textbox on my form, but i able to validate on a client side, i havent experience using data-anotation in asp.net and need bit of a help. When leaving the textbox if its empty must validate using caption error.

What I have tried:

<pre> <div class="form-group">
                                <input type="email" class="form-control" id="textEmail" placeholder="Enter Email" required="required">
                                <div>
                                    <label id="labelMessage" class="text-danger" style="display:none">Invalid email address.</label>
                                </div>
                            </div>
                        </div>
                    </div>
                </div>
            </section>
        </div>
    </div>
    <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>
    <script type='text/javascript'>
        $(function () {
            //When the blur event occurs from your Textbox (you lose focus)
            $('#textEmail').blur(function () {
                var email = document.getElementById("textEmail").value;
                var expr = /[a-z0-9._%+-]+@[a-z0-9.-]+\.[a-z]{2,}$/;
                if (!expr.test(email)) {
                    document.getElementById("labelMessage").style.display = "inline";
                }
                else {
                    document.getElementById("labelMessage").style.display = "none";
                }
            });
        });
    </script>