While browsing the internet, you've most likely heard people mention different web scripting languages? What are they? What do they do? What do they stand for? You'll find all the answers here! I've tried to list some of the most common languages for your benefit

HTML
Probably one of the languages you will hear about the most, HTML stands for Hyper-Text Markup Language. HTML is the main language used to code websites. Without HTML, there would be no websites! If you opened up the source code for this page, and looked throuugh it, you'd find little bits of code that look <b>like</b> <i>this</i>. The things like <this> are called tags. Tags can either affect what's on the page at that spot, e.g. <img src="hello.gif"> would place an image with the filename "happy.gif" in that spot on the page. Or they can affect what comes between them, e.g. <u>Hello!</u> would show up as Hello!. Note the ending tag (</u>) that tells the browser when to stop underlining the text.
File extensions: .html, .htm
Find out more: http://www.w3.org/html/

XHTML
XHTML stands for Extensible Hyper-Text Markup Language. It is designed to show as both XML (See below) and HTML, allowing a wider variety of browsers to view it properly. XHTML users must conform to certain rules, such as tags must be written in lowercase, and elements cannot overlap.
File extensions: .xhtml, .html, .htm
Find out more: http://www.w3.org/MarkUp/

XML
XML stands for Extensible Markup Language. It is similar to HTML, except it's designed to be used not only in web browsers, but a wide variety of other programs. XML offers an easy way to lay things out in an application. XML is also designed to be clear and concise, and easy readable by people. XML allows you to create tags that will appear differently in a program, and therefore making an extremely flexible language.
File extension: .xml
Find out more: http://www.w3.org/XML/

CSS
CSS stands for Cascading Style Sheets. CSS is used to style a website, setting colours, backgrounds, fonts etc. Without excessive use of tags surrounfing the whole page. A typical CSS Sheet would look like this:
body { background-color: #DDDDDD; font-family: Verdana; font-size: 10px; color: #000000; }
a:link { text-decoration: none; color: #FF0000; }
a:active { text-decoration: none; color: #FF0000; }
a:visited { text-decoration: none; color: #FF0000; }
a:hover { text-decoration: underline; color: #00FF00; }
As you can see, we declare what element we're setting the style of (e.g. body), then inside { } brackets, we define the style attributes in the form attribute: value;. Style sheets can be placed within <style> tags in the head of the document, called from an external style sheet using the <link> tag, or the style for a particular element can be set using the style="" attribute.
File extension: .css
Find out more: http://www.w3.org/Style/CSS/

PHP
PHP stands for Hypertext Preprocessor (Don't ask me how!) It's a server-side scripting language, which means it's interpreted and converted to HTML before the browser recieves it. PHP is placed within <?php ?> tags in a document. To interpret PHP, you must be accessing the document through a server that can interpret PHP, rather than just locally. PHP is used for many things, connecting to databases, creating cookies, performing calculations and more. It's one of the most used scripting languages, and can be extremely powerful.
File extension: .php (Although you can set other extensions to allow PHP functionality with)
Find out more: http://www.php.net

JavaScript
JavaScript, not to be confused with Java, is a clientside scripting language, this means that the users browser does all the processing. Disadvantages with this are that you're relying on the fact that the user has an up-to-date browser for the scripts to work. JavaScript is placed withing &lt;script> tags, or a source code is defined using &lt;script src="">. JavaScript works like many other scripting languages. It is object-oriented, and is designed to interact with HTML elements.
File extension: .js
Find out more: http://www.javascript.com

SQL
SQL stands for Structured Query Language. It's the language used by SQL Database managers, such as MySQL, to carry out requests. Although it isn't a very large language, it's important for every webmaster using Databases to know. To get all results from a table using SQL, we would call "select * from tablename;", or if we wanted to select a specific column and a specific row, we could call "select lastname from tablename where firstname = 'John';"
All commands in SQL require a semicolon at the end, except for when using PHP's SQL functions, or when using the "use" function, to switch databases. SQL can be either called directly, or SQL commands can be read from a file.
File extensions: .sql
Find out more: http://www.sql.org/

AJAX
AJAX isn't really an entirely different language, but people use it to refer to the funtions in JavaScript used to remotely access a webpage. This is extremely useful for Webmasters who don't like the idea of reloading pages all the time to refresh information.
Find out more: http://en.wikipedia.org/wiki/Ajax_(programming)

Very nice summary of web related "languages".
PHP: PHP Hypertext Preprocessor is a recursive acronym meaning that the definition of the acronym contains the acronym. I couldn't possibly think that far ahead in naming a language nor poses the skill to write my own language which leads me to believe that the originators are pretty smart people.

I did think that given the importance that Perl has played in the development of web based applications, it should also be mention.
Perl (Practical Extraction and Report Language) is usually what is running when you see anything that uses the cgi-bin directory. It is a very powerful language and was the main server side parser before PHP. File extensions include .cgi and.pl

ASP (Active Server Pages) is also a common language for the web. Personally, I don't use it and don't have little personal information about the language but thought it should be mentioned. It is limited in usefulness since support on Unix/Linux based web servers (usually running Apache) isn't very good which is problematic since the vast majority of web servers use this platform. ASP is a Microsoft language and as a result is rather complex but very powerful!

I like the point that you made about PHP parsing the script into HTML prior to being sent to the browser. Many people don't understand this. In fact, most people don't understand that there are only four ways to display information as a web page. HTML, JavaScript, Plain Text, and graphical (through JS or HTML usually). These are the only formats that your browser will understand. While it is possible to code a website entirely in JavaScript, I don't recommend it.

vujsa

Nice summaries there, it's amazing at how many languages there are and most can acomplish the same things in a different way, more or less efficient. Choosing a language can simply be seeing what you want to do, what you already know and what seems the easiest. There is so much to choose from and i find most are based more or less around a general concept.

-HellFire

I prefer using XHTML over HTML. It is the next generation of web languages, and many sites are currently adopting it.

Oh and by the way, you forgot about XSLT, XLink, XForms, MathML, and SVG, which are XML-based languages that should be mentioned at least a little with XML.

Well, yeah a lot of people today prefer to use xhtml over html4, but as in some topics on this forum, it has been said, that most of people use xhtml for not the purpose it was created, but I also use it, due to it is more strict than html4, when html5 will become a standard for most, some people might notice that even really good designers still use html4, because they understand that it won't change the layout a lot if they will move to xhtml, also if xhtml2 comes sooner as a standard than html5, when it will be hard..

Great summaries, and I'm sure they will help a lot of people; however, you left out a few =[. Languages such as Python, SMARTY, and PERL are still used on the web (though less commonly), and should be included as well, along with the other languages previously mentioned.

As to the html over xhtml debate..I personally believe xhtml is the future of static web design, rather than HTML 5. Obviously HTML 5 will be wider used, as it will be more supported by programs, but the majority of good web developers will probably use xhtml. It loads faster, and works better across many browsers than HTML 4.0 does, plus it utilizes good practices in coding such as ending statements (tags in html), and properly nesting code, which must be done in almost all programming languages.

I do as well. However, I do question what the advantage really is. People say that XHTML is a lot more strict so webmasters are forced to do things the standards-compliant way. However, this is only if these webmasters actually bother checking to see if their website validates. If they don't bother to do this, then XHTML will have the same problem as HTML--there will still be many mistakes.

Moreover, there are some changes in XHTML that I think are rather pointless----<strong> instead of <b>? What's the difference besides an arbitrary change in wording? Besides, <b> is actually shorter than <strong>, so why the change? Then there's <center>, which is actually a very very useful tag. There isn't an easy way to do centering with CSS on all browsers. (It's a hack, basically.)

Nonetheless, XHTML still has its good points, or else I wouldn't be using it. I've heard that it scales nicely to other non-computer platforms like cell phones and such. Always useful, I guess. Though that does make me wonder why Google doesn't switch to XHTML...considering all their new mobile technology and all.

xhtml is strict for the only reason that it should be, it is used with xml which most of people doesn't use and the data should be well written or else the data will be corrupted, in other way, html4 and eventually html5 isn't so strict, but the idea behind it is to show the code as better as possible even with not valid documents, that is usually called transitional..

and changing <b> tag to <strong> or <i> to <em> is a logical way to do, CSS is used to do everything with appearance, that includes bold, italic and center, html or in this way xhtml doesn't need to do anything with the appearance of the website/layout whatever, it needs to deal with data and it needs to be valid by xml tools, html even wasn't designed to do such things like addition of colours, it was the browsers which added this stuff and w3c agreed with it until css and xhtml came in ~1999.. and today, if you want to use b tags and etc. just use html4 and it will validate and you won't have any problems with most of the browsers parsing the documents.

I personally prefer html. xhtml is edsigned to be strict, but it isn't like you can't be strict with html. And I think some parts of xhtml are unnecessary, such as /> at the end of tags that don't have a closing tag. I personally think that having a tag like this: <br /> looks alot messier than a tag like this: <br>. But that's just my opinion. I don't like unnecessary spaces.

i rather xhtml over html (as u no jay) cos when im making a page it has to be strict so when i go back over it for some reason like changing or updating, i know where everything is and no which tags to play with and make sure im not using the wrong tag.

xhtml is cleaner to read so when you are on a site copying or learning from the code, its easier to know what it all is.