title: How to validate a field before whole form validation using ValidationEngine
body: <p>I'm trying to use ValidationEngine (<a href="https://github.com/posabsolute/jQuery-Validation-Engine" rel="nofollow">https://github.com/posabsolute/jQuery-Validation-Engine</a>)
  I need to validate one field (for email) before the whole form will be validated:</p>
  
  <pre><code>$(document).on("click", "#EmailButton", function(){
      var valid=$("#Email").validationEngine('validate');
      alert(valid);
  })
  $("#&lt;?=$formName?&gt;").validationEngine({
     promptPosition:'topLeft', 
     scroll: false,
     binded: false,
     onValidationComplete: function(form, status){
  if(status==true){                    
             $.ajax({
                  type: "POST", ... ... ... }
  }
  </code></pre>
  
  <p>So, when I click on <code>#EmailButton</code> the <code>#Email</code> field should be validated, not whole form.</p>
  
  <p>But when the <code>#EmailButton</code> is clicked, the ajax script from <code>$("#&lt;?=$formName?&gt;").validationEngine({</code>   is run! </p>
  
  <p>I need this feature because I want to make some changes in the form after the <code>#Email</code> field is filled (if email is in Database or not).</p>
  
  <p>How can I validate the <code>#Email</code> field before to run the <code>$("#&lt;?=$formName?&gt;").validationEngine({})</code> script ?</p>
  
  <p>Thanks.</p>