Questions: Frequently Asked Questions

Questions

• Which graphical formats are currently readable by browsers?
• What is PHP and MySQL?

Answers

Which graphical formats are currently readable by browsers?

If you make updates or changes to your site on your own, make sure you use the JPEG, GIF or PNG image formats. Every other formats, such as PICT or BMP, are non standard and may not work at all on some browsers. More on this topic:

• JPEG is optimised for images with thousands of colors (like photographs or images with gradients) but its compression algorithm is lossy, meaning that once compressed, a file will lose some of its definition and cannot go back to the original quality. In this situation, JPEG images are lighter than GIF images.
• GIF is optimised for images with 256 colors or less, like small graphical buttons or simple drawings. In this situation, a GIF image is usually lighter than JPEG.
• PNG, somewhat of a new comer to the scene, is a standardised, open source file format, and could very well be the choice of the future. It operates in two modes, one close to GIF with images having limited colors, or the other like BMP, with a much better compression algorithm, but not as good as JPEG, with images having thousand of colors or more. Furthermore, PNG do not have a lossy compression, so it can be used for other functions like publishing, digital photographs, etc.

What is PHP and MySQL?

PHP is a programming language whose instructions are executed on the server hosting the page, and not the client downloading it (like Javascript, for example, which is executed by the user's browser). It allows generating different HTML pages according to the user's input and actions, and create what we call a dynamic web site. When you see an URL on a page containing various variables (like index.php?template=2&story=/news/sunspots.html), those variables can determine what article, layout, design will be received according to the choices you made. Web sites are free to create thousand of articles while the layout is handled in only one file, which can easily be updated. This is only an example, most applications that you encounter on the web, like discussion boards, polls, calendars, web mail, etc. are written in PHP or a similar language (like Perl, or ASP). As long as you need operations with logical decisions (if this, then that), you need to execute it on the server with such languages. HTML is exclusively structural and static, describing what the content is.

MySQL is a database language where you can save, organise and sort a lot of data. All these operations alllow, for example, the management of a catalog with thousands of items and the possibility to view them in alphabetical, price or popularity order.

There are alternatives, but these two languages are the fastest and the most common, while being free and open-source. There are the usual default choice with a hosting account on Unix/Linux/Apache, while still being available on Windows. We can create almost any kind of web product by combining those two languages, the only limit being the development time, budget and knowledge of the programmer.