[ruslan_mart]

function callback() {
   var ms = this.id.split('_');
   //...
};

window.addEventListener('click', function(event) {
   var target = event.target;
   while(target) {
       if(target.classList.contains('cn')) {
            callback.call(target, event);
            break;
       }
       target = target.parentNode;
   }
});