title: How to cancel submit on AjaxForm
body: <p>i'm working with jquery plugin(ajax form), i try to implementing something like this</p>
  
  <pre><code>$("#MyFormID").ajaxForm({
      dataType: "json",
      resetForm: true,
      beforeSubmit: function() {
         //validateData returns boolean
         if(validateData()){
            // continue submit
         }else{
            //cancel submit
         }
      },
      success: function(json) {
          //show success notification     
      }
  });
  </code></pre>
  
  <p>is there a way to stop the ajax from submiting the form?.
  on beeforesubmit function maybe?</p>