onItemCheck

called when the checkbox inside the tree item was checked

void onItemCheck(id id,boolean state,Event e);

idthe id of the related item state

booleanthe checked/unchecked state of a checkbox e

Eventa native event object (absent when the threeState property is enabled)

tree.attachEvent("onItemCheck". function(id, state, e){
    webix.message("Item " + id + " was " + (state? "checked" : "unchecked"));
});