title: How to add html attribute without value in @Html.BeginForm
body: <pre><code>@using (Html.BeginForm("", "actionname", FormMethod.Post, new { id = "card-activate-form" , data_parsley_validate="true" }))
  </code></pre>
  
  <p>will render </p>
  
  <pre><code>&lt;form action="actionname" data-parsley-validate="true" id="card-activate-form" method="post"&gt;
  </code></pre>
  
  <p>but ideally it should be 'data-parsley-validate' only</p>
  
  <pre><code>&lt;form action="actionname" data-parsley-validate id="card-activate-form" method="post"&gt;
  </code></pre>
  
  <p>how to add data-parsley-validate only in the form</p>