title: Alertify in Button
body: <p>How to show an alert when an input is empty?</p>
  
  <p>Here's the code..</p>
  
  <pre><code>function rfc_vacio(){
    if ($('#RFC_v').val() == "") {
          alert("Empty");
          $('#RFC_v').focus();
          return false;
        }else{
          return true;
        }
  }
  </code></pre>
  
  <p>i want to changue to alerfity,im new on bootstrap</p>