Perl-compatible regular expressions in PHP

Perl Compatible Regular Expressions (normally abbreviated as 'PCRE') offer a very powerful string-matching and replacement mechanism that far surpasses any other search and replace function.

Regular expressions are often thought of as very complex—and they can be at times. However, properly used they are relatively simple to understand and fairly easy to use. Given their complexity, of course, they are also much more computationally intensive than the simple search-and-replace functions. Therefore, you should use them only when appropriate—that is, when using the simpler functions is either impossible or so complicated that it’s not worth the effort.

Make textarea auto-height as you type using jQuery

jQuery is one of the most popular JavaScript frameworks, a fast and concise library that simplifies HTML document traversing, event handling, animating, and Ajax interactions for rapid web development.

How to programatically change a template file in drupal 6

When building modules in drupal, you often would like to change the template file of a specific hook, for example page.tpl.php.
Drupal does not have a special function to do this, but you can play with these 2 functiones:

Singleton design pattern in PHP

You can find all the information you need on the web if you google singleton design pattern. So I'm not gonna fill your head with all the theory.

I'll tell you how you can implement it.

How to fit an image in a rectangle area in PHP using GD

Have you ever had a fixed space in your design, and you must put an image that fits exactly there, while preserving the aspect ratio? Well, this is what i'll explain in this article.

Using a transparent PNG image as watermark in PHP

Sure there are plenty of scripts on the internet that does this thing ... but very few explain this.

Calculate the distance using lattitude, longitude and ZIP codes in MySQL

So, assuming we have a table:

ZIP_CODES
zip_code | lattitude | longitude

We take this zip code from NY
$zip = 10001
$lat = 40.750742
$lon =-74.52976

What we need is the Earth radius (6371 km).

If we need to search the zip codes that are in a 10 km area, we could use this 'small' sintax: