Form Validation with JavaScript - Rock On

(Page 4 of 10 )

You've probably already used JavaScript objects before. For example, the code...

<script language="JavaScript">
a = new Image();
</script>

... creates a new instance of the Image object, while...

<script language="JavaScript">
x = new Date();
</script>

... creates a new instance of the Date object.

JavaScript comes with numerous built-in objects, each with pre-defined methods and properties. But what if you want to roll your own?

Well, it isn't very difficult. As a matter of fact, it's almost identical to writing a JavaScript function.

<script language="JavaScript">
// object constructor
function Band() 
{
...
}
</script>

You can create an instance of the Band object like this:

<script language="JavaScript">
// object instance
obj = new Band();
</script>

Note the all-important "new" keyword - this is how JavaScript knows that you're trying to create an instance of an object, rather than merely running a function.

The code above creates an instance named "obj" of the object Band. You can verify that it is indeed an object by popping up an alert().

<script language="JavaScript">
obj = new Band();
alert(obj);
</script>

Next: Hammer Time >>
 

More JavaScript Articles
More By Nariman K, (c) Melonfire

Comments On: Form Validation with JavaScript

>>> Be the FIRST to comment on this article!