User Guide

68 Handling Component Events
Using the handleEvent callback function
You can also use listener objects that support a handleEvent function. Regardless of the name
of the event that is broadcast, the listener object’s
handleEvent method is called. You must
use an
if..else or a switch statement to handle multiple events. For example, the following
code uses an
if..else statement to handle the click and change events:
// define the handleEvent function
// pass it evt as the event object parameter
function handleEvent(evt){
// check if the event was a click
if (evt.type == "click"){
// do something if the event was click
} else if (evt.type == "change"){
// do something else if the event was change
}
};
// register the listener object to
// two different component instances
// because the function is defined on
// "this" object, the listener is this.
instance.addEventListener("click", this);
instance2.addEventListener("change", this);