HTML 4.01
HTML stands for HyperText Markup Language and is the predominant language for coding websites, with version 4.01 being the latest version. The World Wide Web Consortium (W3C) developed HTML 4.01 and provides standards on how it should be used and all sites that I create meet these standards. I code in pure HTML rather than using a program to create it and have done so for the last four years.
XTML 1.1
XHTML stands for eXtensible HyperText Markup Language and is a blending of HTML 4.01 and XML (Extensible Markup Language). XHTML is much more strict but there is little difference between it and HTML and so I have found it very easy to pick up the few times I have used it.
CSS 2.1
CSS stands for Cascading Style Sheets which define how different elements of a web page appear to the user whether on screen or printed. It is now good practice to define the layout of web pages using CSS as opposed to using tables which was common in the past, all of my sites are laid out purely using CSS.
PHP 5
PHP is a server side scripting language where the web server takes PHP code as input and outputs HTML to the users which allow web pages to be created dynamically. PHP is particulary useful alongside mySQL for creating, modifying and viewing databases and so can be used to create ecommerce websites and content management systems.
Javascript
Javascript is a client side scripting language that allows the web page to respond to the users actions, for example showing or hiding something based on a users entry on a form. Javascript is also useful for form validation so that the user can fix any errors before the form is submitted.