$('#cmdRegistrar').attr('disabled','-1')

$('#cmdRegistrar').removeAttr('disabled')

$("#BOTON").click(function() {		
       //se deshabilita control				   
       $('#BOTON').attr('disabled','-1');
        /* instrucciones javascript*/		
         $.ajax({
                  type: 'POST',
                  url: 'index.php',
                  data: 'acciones.php?action=algo',
                  success: function(data) {				
                            /* instrucciones javascript*/		
                           //se quita atributo DISABLED
                           $('#BOTON').removeAttr('disabled');		
                   }
         });//fin ajax	
});