XHTML is the 'markup' language used to create the basic structure of a web page - page divisions, headings, lists, tables, paragraphs and the like. This markup tells your browser what to show you when it reads (or in technical terms, 'parses') the code for the web page you want to look at.
CSS is used alongside XHTML to produce the distinctive styling features of a web page. CSS can be very simple - for setting font colours, for example - or much more complex - positioning page elements precisely on screen, producing roll-over effects on links, and a lot more.
There are many programming languages available to web developers but perhaps the most popular and easy to use of them is PHP. Wilson Web Design uses PHP because it is a powerful, stable and well-proven web programming tool which works extremely well with its open-source stable mate, the powerful MySQL database management system.
My SQL is an extremely powerful database that can be used with web scripting languages to create all kinds of user interactivity.
Like PHP, MySQL is an open source tool that dominates the web database world. It's proven, reliable and flexible and can be used to store all of your web-related data.
When a user first visits a web page he has to wait for the whole page (text, images, Flash animations, etc) to download before he can see it in its entirety. Using AJAX comes in useful when the user wishes to update some data on the page, perhaps by clicking on a button or link.
AJAX programming techniques allow web pages to be updated without the need for a full page refresh - when a user chooses some interactivity a single request is sent on its own to the web server and the page is updated without the rest of the content being re-sent as well.
Click the button to see AJAX in action: