Here's the model, note that the Compare attribute decorates the ConfirmEmail property on the model:

    using System.ComponentModel.DataAnnotations;

    namespace jQuery.Validation.Unobtrusive.Native.Demos.Models
    {
        public class EqualToModel
        {
            [Required,
             EmailAddress]
            public string EMail { get; set; }

            [Compare("EMail", ErrorMessage = "Emails do not match.")]
            public string ConfirmEmail { get; set; }
        }
    }
        

Here's the view (which uses the model):

    @model jQuery.Validation.Unobtrusive.Native.Demos.Models.EmailModel
    @using (Html.BeginForm())
    {
        <div class="row">
            @Html.LabelFor(x => x.EMail, "An email address must be entered:")
            @Html.TextBoxFor(x => x.EMail, true)
        </div>

        <div class="row">
            @Html.LabelFor(x => x.ConfirmEmail, "Please confirm your email address:")
            @Html.TextBoxFor(x => x.ConfirmEmail, true)
        </div>

        <div class="row">
            <button type="submit" class="btn btn-default">Submit</button>
            <button type="reset" class="btn btn-info">Reset</button>
        </div>
    }
        

Here's the HTML that the view generates:

    <form action="/Demo/EqualTo" method="post">
        <div class="row">
            <label for="EMail">An email address must be entered:</label>
            <input data-msg-email="The EMail field is not a valid e-mail address." 
                data-msg-required="The EMail field is required." 
                data-rule-email="true" 
                data-rule-required="true" 
                id="EMail" name="EMail" type="text" value="an@emailaddress.com" />
        </div>
        <div class="row">
            <label for="ConfirmEmail">Please confirm your email address:</label>
            <input data-msg-equalto="Emails do not match." 
                data-rule-equalto="#EMail" 
                id="ConfirmEmail" name="ConfirmEmail" type="text" value="" />
        </div>
        <div class="row">
            <button type="submit" class="btn btn-default">Submit</button>
            <button type="reset" class="btn btn-info">Reset</button>
        </div>
    </form>
        

Here's the JavaScript that initialises the validation:

  $("form").validate({
      submitHandler: function (form) {
          alert("This is a valid form!");
      }
  });