Introduction to XHTML
So you want to learn XHTML? You may have heard about it as you transit from HTML onto more advanced web development topics or you may have been told about it when you began learning about web development, or one of many other reasons. You can use XHTML to create your own web content and publish your work online. XHTML is an important tool in creating web content.
This lesson focuses on:
- What is XHTML?
- What XHTML is not
- XHTML file extensions
- Support for XHTML
- The world wide web
- The HTTP protocol
- The HTTPS protocol
What is XHTML?
XHTML is a web language used to write webpages. With XHTML, you decide where to arrange text and graphics on web pages as well as their structure and layout. XHTML is designed to specify the logical organization of a webpage. Some other web languages include Javascript, VBScript, and PHP.
XHTML stands for Extensible Hyper Text Markup Language. It is the next phase in the evolution of HTML. The last version of HTML before XHTML was HTML 4.01. The first version of XHTML was XHTML 1.0, and the current version of XHTML is XHTML 1.1. XHTML is alot like HTML, in fact it is almost identical to HTML 4.01, but cleaner and stricter in its syntax. While it has not done so yet, XHTML is aimed to eventually replace HTML.
NOTE: XHTML is a W3C Recommendation.
Before you begin studying XHTML, you should already have at least a basic understanding of HTML and webpage building. You can learn all about HTML in our HTML section. XHTML uses the same tags as HTML 4.01 to markup data.
What XHTML is not
XHTML like its predecessor HTML, is a static language. This means that the content you create with XHTML does not change, it is not dynamic. XHTML is used to create and place various elements on a webpage, it is not used to create things like calculators and other things which would require dynamic data.
Dynamic content can be created with languages such as as Javascript, VBScript, and PHP.
XHTML file extensions
XHTML files have a .html or .htm file extension just like HTML files.
Support for XHTML
XHTML is supported by all new browsers and it is compatible with HTML 4.01
The world wide web
XHTML like HTML, is used to create web pages on the world wide web, but what is the world wide web? When it comes to the world wide web, a common misconception exists that the world wide web and the internet are synonomous. The world wide web is only a small subset of the internet. The world wide web is the medium by which webpages and other resources such as sounds and images are transferred from various web sites and users send requests for these resources as well as data to web servers. The word 'internet' is an abbreviation for 'internetwork' and it is the global communications system which links together various computer networks around the world allowing for intercommunication between devices and people on different networks. The global communications system which is the internet employs various different protocols to allow for intercommunication between devices and people on different networks. One of these protocols is the HTTP protocol.
The HTTP protocol
HTTP stands for Hyper Text Transfter Protocol. It is this protocol that is used to transfter data across the world wide web. Every time you enter a websites URL in your web browser (ex. www.google.com), your web browser is making use of the HTTP protocol to send your request for a webpage and then transfer the data to you. The data for a website is stored on a computer called a web server.
The HTTPs protocol
While HTTP is used to transfer data across the world wide web, there is another protocol which works just as HTTP does, but adds a level of security. This protocol is the HTTPS protocol. HTTPS stands for Hyper Text Transfer Protocol Secure. HTTPS is used to encrypt communication between a web browser and a web server. HTTPS is often used on websites that need to provide private communication such as online stores and membership sites. Next time you are making a purchase from an online store look at your web browsers address bar, the beginning part of it should say HTTPS.
