What is php?

Php is a scripting(or programming) language originally created by the Danish/Greenlandic programmer Rasmus Lerdorf in 1994 as a set of tools he used for maintaining his Personal Home Page(hence PHP) and for performing such tasks as displaying his resume and recording how much traffic his website recieved. Php allowed for more dynamic webpages which could communicate with databases and have a lot more functinality than standard html webpages.

It was released publicly in 1995 free and open source(meaning that code is shared openly), and thus has elvolved and continues to do so.

There's plenty of history and other such information out there if you are interested, but my tutorials aren't history lessons, we're here so that you can learn how to use it.

client side and server side

Php is a "server side" scripting language. What the heck does that mean??

First of all, computers generally only understand zero's and one's(known as binary code) which dosn't make it very easy for us humans to tell a computer what to do so we have various scripting or programmimg languages that we humans can understand and use a little easier.

Html is one language we use to design webpages, our web browser(which is actually a program or a piece of software) then translates our html code into zero's and one's for our computer so that our computer knows what we want it to do.

Html is what we call a "client side" language. Css and JavaScript are also client side.

But what the heck does that mean already?? Client side, server side, what is all this??

Well your web browser, apart from being called a browser, a program, a piece of software and probabaly every swear word under the sun, is also called a "client". With this being the case, your web browser interprets client side code and displays the results for us.

As for server side, if you've followed the rest of my tutorials, particularly publishing lesson 2, then you should know what a server is.

If you havn't added 1 and 1 to come up with 2 yet, basically with any server side code, the server interprets the code and performs any programmed functions within that code) before sending it to our browser, which then displays the final results.

If you remember back in html lesson 6 we discussed the source code. This tutorial webpage you are viewing right now is written in php. Yes it still has html, and some css. If you look at the source of this page though all you will see is the html and css, you won't see any of the php code, why? That's right, because your browser dosn't recieve the php code, it only recieves the results of the code which was executed on the server previous to any information being transfered to your computer.

Lesson added Friday 1st May 2009