Using "this" Keyword to Represent Current Object

JavaScript Tutorials - Herong's Tutorial Examples

∟Using "this" Keyword to Represent Current Object

This section provides a quick description of the 'this' keyword, which represents the current object in object method. A tutorial example is provided on how to access properties and methods of the current object.

While defining a function to be used as a method for objects, you can use the keyword "this" to represent the current object the method is called against. The "this" keyword in JavaScript has the same usage as in Java.

Here is tutorial example of using "this" keyword to access properties and methods of the current object:

<html>
<!-- Object_this_Keyword.html
   Copyright (c) 2008 HerongYang.com. All Rights Reserved.
-->
<head>
<title>"this" Keyword in Object Methods</title>
</head>
<body>
<pre>
<script type="text/javascript">

// Using "this" to get the properties
function myToString() {
   return '"'+this.title + '" by '+this.author;
}

// Using "this" to get the "toString" method
function showAll() {
   window.alert(this.toString());
}

   // Preparing one of "Object" type
   var myBook = new Object();
   myBook.author = "Herong Yang";
   myBook.title = "JavaScript Tutorials";

   // Adding a new method to one object only
   myBook.print = showAll;
   
   // Overriding "toString()" on one object only
   myBook.toString = myToString;

   // Calling the method on "myBook"
   myBook.print();
</script>
</pre>
</body>
</html>