var noajax = false;

  function CheckRegisterForm()
  {
    chkform = document.frmRegister;
    var re_email = /^[_a-zA-Z0-9\-\_\.\+&]+(\.[_a-zA-A0-9\-\_\.\+&]+)*@[a-zA-Z0-9-\.]+(\.[a-zA-Z-9\-\.]+)*(\.[a-zA-Z]{2,4})$/;

    // disable submit button
    $('btnRegisterSubmit').disabled = true;

    if (!noajax)
    {
	    // get form parameters
	    var parameters = $('frmRegister').serialize(true);
	    // add 'ajax' action parameter (to return JSON)
	    parameters['action'] = 'checkajax';
	    
	    // do ajax request
	    new Ajax.Request('/register.php', 
	      { method: 'POST',
	    	  parameters: parameters,
	    	  onSuccess: RegisterSuccessHandler,
	    	  onFailure: RegisterFailureHandler
	    	}
	    );
    
      return false;
    } else 
    	return true;
  }
  
  // handles result of Ajax request when succeeded
  var RegisterSuccessHandler = function(transport,json) 
  {
  	// handle error messages
    if (json.status=='error')
    {
      ErrorDialog(json.errors);
    }

    $('btnRegisterSubmit').disabled = false;    
    
    // okay, go to confirmation page
    if (json.status=='success')
    {
      window.alert('Welcome');
      document.location = '/index.php';
    }
  }
  
  // handles result of Ajax request when failed
  var RegisterFailureHandler = function(transport) 
  {
  	// submit via normal POST-request without ajax
  	noajax = true;
  	$('frmRegister').submit();
  }