ITC C301 - 201BA - (Individual) Idul - PT2 - 1.2 - Blogging Activity - JavaScript Event Handlers

JavaScript is an Object-Oriented Programming Language. Similar to Visual Basic, JavaScript is capable of running portions of code based on the interactions of the user with its objects. Formally called Event Handlers, these segments of code allow JavaScript to recognize the user's actions, and respond to them appropriately.

There are several Event Handlers available for the aspiring programmer to use, all of which are contingent on what event the programmer desires JavaScript to be able to respond to. We can categorize the JavaScript Event Handlers based on the object that they are usually a part of, as per the following:

Windows Event Handlers:

• onload
• onunload*
• onerror
  

Mouse Event Handlers:

• onclick
• ondblclick*
• onmousedown*
• onmousemove*
• onmouseout
• onmouseover
• onmouseup*

Keyboard Event Handlers:

• onkeydown*
• onkeypress*
• onkeyup*

Form Elements Event Handlers:

• onchange
• onsubmit
• onreset
• onblur
• onfocus
• onselect
  

* not covered in class 

Reference: adapted from 

Lebajan & Esporlas, 2008, HTML and Web Design
and
Valderama, 2021, Scripting Language - JavaScript OOP and Events

As we only have limited class discussions, quite a few of these are not covered in class. Today I will attempt to cover both onmousedown and onmouseup Event Handlers, as they are functionally opposite with each other.

The onmousedown Event Handler takes place if the user clicks and holds any mouse button down. Conversely, the onmouseup Event Handler occurs once the user releases the held button. These Event Handlers are primarily utilized on controls that requires the user to hold down any mouse button to activate, and release the mouse button to stop.

Interestingly, it should be observed that an immediate sequence of both onmousedown and onmouseup simulates an onclick event, and indeed, w3schools lists these three Event Handlers as sequential to each other, specifically for a Left Mouse Button activation, while a Right Mouse Button sequence is composed of onmousedown, onmouseup, and oncontextmenu Event Handlers.

References:
onmousedown Event - https://www.w3schools.com/jsref/event_onmousedown.asp
onmouseup Event - https://www.w3schools.com/jsref/event_onmouseup.asp

Thus concludes this brief blog on two JavaScript Event Handlers. The hope is that this blog piques the reader's curiosity on the other available JavaScript Event Handlers, as there are definitely more Event Handlers available to the aspiring Web Developer.

DISCLAIMER: This blog is primarily used for academic purposes. All contents belong to their respective owners/authors and there is no copyright infringement intended.

Subject Code: ITC C301 - 201BA - Integrative Programming and Technologies

Grading Period: Prelims
Topic: JavaScript Event Handlers
Date: 11 February 2021

Author: Idul, Manuel Mark; 20-257214