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Rock On - JavaScript

javascriptForm validation can help to reduce the amount of bad data that gets saved to your database. In this article, find out how you can write a simple JavaScript form validator for basic client-side validation, and learn a little bit about JavaScript OOP in the process as well.

  1. Form Validation with JavaScript
  2. Check Point
  3. Object Lessons
  4. Rock On
  5. Hammer Time
  6. How Things Work
  7. A Little Space
  8. Expressing Yourself
  9. Under Construction
  10. A Quick Snack
By: Nariman K, (c) Melonfire
Rating: starstarstarstarstar / 464
December 01, 2003

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

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

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

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

... 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() 

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

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

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();

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

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