ralphje.net Blog

A common problem found by starting PHP programmers is the warning:
Warning: Cannot modify header information – headers already sent by (output started at index.php:1) in index.php on line 3
Before understanding this problem, you have to know how pages are transmitted using the HTTP-protocol.  Any page or image you receive looks like this:

HTTP/1.x 200 OK
Date: Thu, [...]

A very long time ago, the idea of the internet was providing static information. For a long time already, this isn’t true anymore. User-generated and dynamic content are common nowadays and web developers are still trying to keep their applications up-to-date with the latest developments.
However, they are becoming lazy and are getting confused. They are [...]

MySQL is a powerful database engine, especially in combination with PHP. But how do you retrieve information from a dabatase?
In this post I’ll try to explain the difference between mysql_fetch_array, _assoc, _field, _length, _object and _row.

The best way for saving user data using PHP are Sessions. They come in different flavours: at first, there’s the one that makes your URL ugly, but makes them usable for all users. Secondly you can use cookies. That’s much nicer, but doesn’t work for all browsers. Surf2me.nl uses the latter.
Sessions
But what are sessions? It’s [...]