Iterate form elements

Webix JS
#1

Hi,
I need to check all the elements of my form for presence of some css class in any.
How can I iterate by form elements and check each one?

#2 
for (var key in $$("form").elements){
   var el = $$("form").elements[key];
   //el  - webix view
   //el.getNode() - HTML node
   //el.config.css - css class from initial config
}