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Wednesday, November 11, 2009

An introduction to web technologies - part 2

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In my very first blog, I talked a little about the two languages that are the fundament of every web page - HTML and CSS. HTML defines the structure of a web document - page header and page body, headlines, paragraphs, lists, links, images and so on. CSS takes care of the looks - colours, fonts, text size, spacing, borders, and a host of other features. The main limitation of CSS, these days, is that not all browsers support all of its features! But I am sure that in a few year's time, that won't be so much of an issue any more.

Today I would like to introduce another web language which has become a standard over the last five or so years. The first time I stumbled across a PHP based website, it seemed like something that was way beyond the reach of mere mortals. Login systems, online message boards and forums, image galleries which can be updated and sorted according to different criteria (title, date, popularity, and so on), file uploads, page search functions, a little line that greets you with your name when you log on - not so many years ago, these fancy features were the domain of big money clients who could afford a programmer or fifteen, to develop a site from scratch.

Not any more, these days. PHP is but one of several web scripting languages that work together with a database to create all the features I have mentioned above, and more. But it has become the language of choice for many web designers - especially those who work on their own - because it is an open source language. Meaning, one does not have to invest in an expensive software package to use it - the code is free, if you know how to write it. There is also a large and enthusiastic community of geeks out there who are most generous with code snippets and advice - it always amazes me just how much knowledge and information is available at a mouseclick on the internet, once one has mastered the basics and knows what those geeks are talking about!

The basic function of PHP is to generate HTML code, which can then be displayed as a web page. This means that rather than having to build each and every single web page individually, one can now let the PHP script do the work. Take, for instance, a product catalogue (or any image gallery, for that matter). In a purely HTML based site, one would have to go in and change the HTML code every time a new product is added to the catalogue - image, description, price, etc. - in every web page where that new product is mentioned.

With a PHP based site, the new product is added to a database (usually via an easy to use file upload manager) and the PHP script pulls that information from the database and builds it into the web pages where appropriate. A heck of a lot less work! And much less potential for errors and oversight.

There are a whole lot more things that PHP can automate - from automatically displaying the correct "page last updated" date, to personalized pages for visitors based on user information submitted through a login system. They are too many to cover in one blog. The main point, however, is that PHP makes these advanced features perfectly accessible even on a relatively modest budget. Want to know more? Ask me about it! :-)

Asni: Multimedia Art & Design:: ::