occurs immediately after the component has been rendered.
some.attachEvent("onAfterRender", function(){
//... some code here ...
});
The event fires each time the component is redrawn, not only after the component has been created.
To catch the moment of creation, supply it with webix.once() helper:
some.attachEvent("onAfterRender", webix.once(function(){
console.log('called once after first rendering:');
}));