Easy JSON Encoding/Decoding in PHP

Update(2009-09-19): JSON encoding and decoding is built into PHP since PHP 5.20. You don't need Zend's JSON support if your PHP version is >= 5.20. Please see:



So you are writing a piece of PHP code to handle some Ajax request and you've just finished coding the business logic. It is time to output some server response so that the page which initiated the Ajax request can obtain the requested result.

You decided to use JSON because you don't want to get your hands dirty by traversing nodes after nodes. After encoding a fairly complex and nested PHP array into JSON, you find out writing such code is very unpleasant and you start wondering if there is an easier way to do this. The answer is yes - Zend Framework will save your day.

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Asynchronous File Upload – YUI’s Approach

YUI is a truly amazing framework for those who are writing Ajax applications. Its JavaScript widgets allow programmer to create richly interactive UI components with ease. However, these UI widgets are not very useful unless the end result of the interaction can be saved to the server side. Hence YUI has added Ajax support to most of its widgets. While many people are familiar with YUI Connection Manager's Ajax capability, only a few know that Connection Manager can be used to simulate Ajax-like file upload.

The theory that makes asynchronous file upload work is not complicate, but the code for it to work can be a little bit lengthy if it was developed from the scratch. Since there no reason to reinvent the wheel and YUI's Connection Manager can take care of most of the dirty jobs for us, in this article, I'll show you how to use it to do a simple asynchronous file upload. Because XMLHttpRequest object does not support file upload, the Connection Manager uses inline frame approach. Basically what the Connection Manager does is it creates an invisible IFRAME for file upload and parses the server response once the upload is completed. In the end, what you get is an illusion of Ajax-like file upload interaction. However, since this is an IFRAME, some Ajax events such as success or failure are not available in IFRAME method as they are available in regular Ajax request in YUI.

Test upload example online

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Protecting Your Site From Spam Bot with CAPTCHA

CAPTCHA provides a simple yet effective way to tell humans and computers apart. The need of CAPTCAH arises because web pages which accept user input such as posting comment are vulnerable to automated spam. It is not a difficult task to write a script that could generate large amount of repetitive information and post them to a targeted page in short period of time. Unless the page is protected, it will soon polluted by those spam.

For instance, the site you are visiting, Code Central, receives over 10 junk comments everyday. Fortunately, WordPress uses an algorithm that can filter out most of these junk comments and flags them for review. The unfortunate part is that administrating them is laborious and frustrating - I don't want to delete them in a batch because I don't want to accidentally delete a comment that is submitted by a real user. So I decided to install a CAPTCHA to see if that is going to help.

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YUI Based Lightbox – Revisited

Note: This script has been updaed

In the previous article of YUI based lightbox, I've shown you how easily one can create a lightbox using YUI's Dialog class. Although the lightbox we created in the previous article has the basic skeleton of a lightbox, it still lacks some crucial features and it looks quite ugly. Luckily YAHOO released YUI 2.3.0 not long ago, which included an eye candy skin (sam) that is more attractive than one bundled by default. We will use the new skin for the revised lightbox. Since we don't need all the features provided by the Dialog class (e.g., submitting data), I replaced the Dialog class with Panel for the container class of the new lightbox.

A picture is worth a thousand words, so here is a screen shot of our new lightbox:

Lightbox Demo Screen Shot

I might have mentioned this before, but I couldn't address enough the helpfulness of a JavaScript framework in dealing with cross-browser compatibility issues. By using a framework, the new lightbox is compatible with majority A-Graded browsers and it was created with minimal effort. Once again, it has been tested in the following browsers: Firefox, Netscape 8.1, IE 6, IE 7, Mozilla 1.7.13, Opera 9.21.

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Debug JavaScript with Firebug

Writing JavaScript is easy, but debugging is not due to the very limited debugging functionalities provided by the JavaScript language itself. One of such limitations is that there's no effective way to display debugging message other than embedding a bunch alert boxes or a million lines of document.write in the JavaScript code. Fortunately, external debuggers can more or less help developers to overcome these limitations and make debugging more pleasant.

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