This section provides a quick description of object's own properties. A tutorial example is provided on how to add, update, and delete object's own properties.
When you create a new object from the "Object" constructor, you will get an object with only two default properties:
"constructor" - This property contains the constructor function of this object.
"prototype" - This property represents the prototype of this object to allow you to modify the prototype on the fly.
But you can add more properties to one object at any time using an assignment operation like this:
object_name.property_name = initial_value;
The added property is for this one object only. Other objects will not have this property.
You can also delete properties from one object at any time using a delete operation like this:
delete object_name.property_name;
Here is a tutorial example that shows you how to add a new property, update the property value, retrieve the property value,
and delete a property.
<html>
<!-- Object_Property.html
Copyright (c) 2008 by Dr. Herong Yang, http://www.herongyang.com/
-->
<head>
<title>Object Properties of "Object"</title>
</head>
<body>
<pre>
<script type="text/javascript">
// Creating objects of "Object" type
var mySite = new Object();
var myBook = new Object();
// Adding a new property to one object only
mySite.url = "herongyang.com";
myBook.author = "Herong Yang";
// Updating a property value
mySite.url = "www.herongyang.com";
// Showing property values
document.writeln('mySite.url: '+mySite.url);
document.writeln('myBoot.url: '+myBook.url);
document.writeln('mySite.author: '+mySite.author);
document.writeln('myBook.author: '+myBook.author);
// Is this property for one object only?
document.writeln('mySite.hasOwnProperty("url"): '
+mySite.hasOwnProperty("url"));
// Deleting a property from one only
document.writeln('Deleting mySite.url...');
delete mySite.url;
document.writeln('mySite.url: '+mySite.url);
</script>
</pre>
</body>
</html>
