CAPTCHA is a simple test to determine if a user is a computer or a human. It is used to prevent spam abuse on the websites. So if you use CAPTCHA on your web site forms, this can help in stopping some bots and making life harder for other bots in accessing or using your forms. The goal of this tutorial is to demonstrate how to make your own simple CAPTCHA protection using PHP and AJAX technologies.
In this article, the first of three parts, you will start creating a simple web-based POP 3 client using AJAX, which will use "XMLHttpRequest" objects to retrieve messages from a mail server.
In this installment, you'll learn how to use images and cookies to enable client-server communication even on older browsers that don't support the DOM.
AJAX is an acronym that stands for Asynchronous JavaScript and XML. AJAX gains its popularity by allowing data on a page to be dynamically updated without having to make the browser reload the page.
In this article I'm going to show you three simple and practical uses for Ajax on your Web site. You'll need to know a bit of HTML, JavaScript, and PHP to follow along, but I'll do my best to explain everything in simple terms so you don't get lost.
This is an example of a good use of Ajax, and at the same time keeps it simple. It is a zip code verifier. As soon as the person enters the zip code it makes a request to the server to see if the zip code is in the database, and returns the city and state.
This article illustrates one method of benchmarking your Ajax applications as well as point out some of the major performance pitfalls that the author has encountered while developing Ajax components and applications.
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