Science Library - free educational site

Event handlers

Personalised Events in JavaScript

Often it is useful to augment the available events by creating personalised events. The simplest method is as follows:

var event = new CustomEvent('eventName');

//Listen to an element:

elem.addEventListener('eventName', function(e){...});

// Trigger

event.dispatchEvent(event);

This method functions on all up-to-date browsers - except Internet Explorer. To make it functionable with antiquated browsers and IE, we can use an alternative method:

function createEvent(eventType) {

try {

return new CustomEvent(eventType);

} catch (error) { // CustomEvent not supported

if (document.createEvent && document.createEvent.initEvent) {

// old browsers

var ev = document.createEvent("HTMLEvents");

ev.initEvent(eventType, true, true);

} else if (document.createEventObject) {

// IE

var ev = document.createEventObject();

ev.eventType = eventType;

} else {

return false;

}

return ev.

}

}

At this point, however, it is necessary to bear in mind that the events created with createEventObject do not have the dispatchEvent method, but use instead fireEvent.

function triggerEvent(element, event) {

if (element.dispatchEvent) {{

element.dispatchEvent(event);

} else if (element.fireEvent) {

element.fireEvent("on" + event.eventType, event);

} else {

return false;

}

return true

}

In this way we can create and use our own personalised events!

Sean Bone

ZumGuy Network webmaster

Visit my Internet forum: ZumGuy Internet Forum

Per una versione di quest'articolo in Italiano vedi: Eventi personalizzati in JavaScript

Personalised Events in JavaScript

Often it is useful to augment the available events by creating personalised events. The simplest method is as follows:

var event = new CustomEvent('eventName');

//Listen to an element:

elem.addEventListener('eventName', function(e){...});

// Trigger

event.dispatchEvent(event);

This method functions on all up-to-date browsers - except Internet Explorer. To make it functionable with antiquated browsers and IE, we can use an alternative method:

function createEvent(eventType) {

try {

return new CustomEvent(eventType);

} catch (error) { // CustomEvent not supported

if (document.createEvent && document.createEvent.initEvent) {

// old browsers

var ev = document.createEvent("HTMLEvents");

ev.initEvent(eventType, true, true);

} else if (document.createEventObject) {

// IE

var ev = document.createEventObject();

ev.eventType = eventType;

} else {

return false;

}

return ev.

}

}

At this point, however, it is necessary to bear in mind that the events created with createEventObject do not have the dispatchEvent method, but use instead fireEvent.

function triggerEvent(element, event) {

if (element.dispatchEvent) {{

element.dispatchEvent(event);

} else if (element.fireEvent) {

element.fireEvent("on" + event.eventType, event);

} else {

return false;

}

return true

}

In this way we can create and use our own personalised events!

Sean Bone

ZumGuy Network webmaster

Visit my Internet forum: ZumGuy Internet Forum

Per una versione di quest'articolo in Italiano vedi: Eventi personalizzati in JavaScript

Content © Renewable-Media.com. All rights reserved. Created : June 3, 2014 Last updated :March 7, 2016

Latest Item on Science Library:

The most recent article is:

Trigonometry

View this item in the topic:

Vectors and Trigonometry

and many more articles in the subject:

Subject of the Week

Computing

Information Technology, Computer Science, website design, database management, robotics, new technology, internet and much more. JavaScript, PHP, HTML, CSS, Python, ... Have fun while learning to make your own websites with ScienceLibrary.info.

Computer Science

Great Scientists

Charles Darwin

1809 - 1882

Charles Darwin is one of the most famous of all scientists, and a true hero of science. His theory explaining the mechanisms of evolution were published in his book On the Origin of Species (1859), which launched a storm of controversy from religious dogma adherents.

Portrait: Charles Darwin
Lugano English

Quote of the day...

"Now, I am afraid my usefulness has ended."
"Maestro Galileo, don't be like that. I promise you you will go down in history."
"That's what my teacher told me. If you don't study harder, he said, you will go down in history."

ZumGuy Internet Promotions

Vitruvian Boy