@using (Html.BeginForm("Edit", "Users", FormMethod.Post, new { id = "myForm" }))
{
    @Html.AntiForgeryToken()

        <input name="username" type="text" value="@Model.Username" class="form-control" maxlength="50" minlength="4" required pattern="[A-Za-z0-9_.-]*" />
}

jQuery.validator.addMethod("usrname", function (value, element) {
        return this.optional(element) || /^[A-Za-z0-9_.-]*$/.test(value);
    }, "Username can only contain lowercase/upercase letters, numbers, underscores, dashes and dots!");

    var val = $("#myForm").validate({
        rules: {
            username: {
                required: true,
                minlength: 4,
                maxlength: 50,
                usrname: true
            },