Introduction (HTML 5 )

  Introduction to HTML 5

 This chapter gives you clear idea about basic concepts of web like WWW, URL, Web Server , Browsers, HTML etc. 

World Wide Web - The world wide web is a network of online content that is organized in HTML and accessed via HTTP. The word refers to all the interlinked HTML pages that can be reached over the Internet. The World Wide Web was actually designed in 1991 by Tim Berners-Lee while he was a contractor at CERN. The World Wide Web is usually referred to as "the Web."

www vs Internet - The World Wide Web is what a lot of people think of as the Internet. It is all the Web pages, pictures, videos and other online content that can be viewed via a Web browser. The Internet, in contrast, is the underlying network connection that allows us to send email and access the World Wide Web.

URL - URL stands for Uniform Resource Locator, and is used to specify addresses on the World Wide Web. A URL is the fundamental network identification for any resource connected to the web.

Web Server - A web server is a system that provides content or services to end users over the internet. Simply put it is a computer that hosts a website on the Internet.

Website - A website is a group of publicly available, interlinked Web pages that share a single domain name. Websites can be developed and maintained by an individual, group, business or organization to provide a variety of purposes. Often it is called a web site or simply a site.

Web Page - A web page or webpage is a file usually written in Hyper Text Markup Language (HTML) that is accessible through the Internet or other network using an Internet browser. A web page is viewed by entering a URL address and may have text, graphics, and hyperlinks to other web pages and files.

Search Engine- Search Engine is a website that helps you find other web pages. Some of the popular examples of search engines are Google, Bing and Yahoo.

Browsers - A browser or web browser is a software program built to access content on the World Wide Web. There have been a number of web browsers that have come and gone over the years. The first, known as World Wide Web (later changed to Nexus), was invented by Tim Berners-Lee in 1990. Some of the current popular browsers are Google Chrome, Firefox, Opera, Microsoft Internet Explorer or Edge, or Apple's Safari.

Operating Systems - An operating system (OS) is system software that manages computer hardware and software resources and provides common services for computer programs. After being initially loaded into the computer by a boot program, OS manages all the other programs in a computer. The most popular desktop operating system is the Microsoft Windows. The macOS by Apple Inc. is in second place, and the varieties of the Linux are collectively in third place. Google's Android and Apple's iOS are dominant operating systems in mobile sector. While in the web server sector Linux has the major market share.

What Is HTML?

HTML is an acronym for Hyper Text Markup Language. Basically, a Web page (or HTML document) is a plain text file that has been encoded using Hypertext Markup Language (HTML) so that it shows up nicely formatted in a Web browser. Here’s what HTML means, word-by-word: 

• Hypertext: Text that you click to jump from document to document. This is a reference to the ability of Web pages to link to one another. 

• Markup: Tags that apply layout and formatting conventions to plain text. Literally, the plain text is “marked up” with the tags.

 • Language: A reference to the fact that HTML is considered a programming language.

How Browsers Style Web Pages - Just like most computer software, a web browser only works with a specified type of file. An HTML page primarily ends in the file extension of .html. When a browser loads an .html document, it begins to redraw the screen according to the included HTML markup and content.

HTML History - HTML first made an appearance in 1990-built upon the pre-existing Standard Generalized Markup Language (SGML) - as the foundational language for the newborn World Wide Web, but it wasn’t officially defined until 1993. It was further refined and extended with HTML 2.0, the first official HTML standard, in 1995. Version 3.2 arrived in early 1997 with a variety of new features, and HTML 4.0 came soon afterwards around the end of the same year.

Setting Up Your Development Environment - 

• Exploring HTML Editors: An HTML editor is a computer program for editing HTML, the markup of a webpage. Even though the HTML web page can be created with any text editor like notepad, specialized HTML editors can provide ease and added functionality. Some of the popular free HTML editors are Notepad++, Sublime Text, Atom, Brackets. 

• Exploring Web Browsers: Because your website users can use different browsers, you need to make sure that your website is cross-browser compatible. For this reason, every web developer must have major browsers like Google Chrome, Firefox, Opera, Microsoft Internet Explorer or Edge, or Apple's Safari. 

• Viewing Source Code in Browser: Underneath all the beautiful images, perfect typography, and wonderfully placed calls to action buttons lies your webpage source code. Every web browser allows you to access the source code of every website. You can access the HTML code of any website by right clicking in the browser window and selecting "view page source".

Three Layers of Web Page: HTML, CSS, JavaScript -

 HTML - Structure or content layer: The HTML code is the structure or content layer of the web page. The way frames of a house generate a solid foundation, upon which the rest of the house is built, so does a solid foundation of HTML produces a platform upon which a website can be created. HTML structure can consist of text or images and it contains the hyperlinks that visitors use to navigate around the web site. 

• CSS - Style or presentation layer: The style or presentation layer dictates how a structured HTML document will look to a site's visitors. This layer is defined by CSS (Cascading Style Sheets). These files contain styles that indicate how the document should be displayed in a web browser.

 • JavaScript - Behavior or interactivity layer: The behavior layer is the layer of a Web page that can respond to different user actions or make changes to a page based on a set of conditions. For most Web pages, JavaScript is the behavior level for the interactions on the page.

HTML Tags - The code within an HTML file is made up of text surrounded by tags. These tags indicate where the formatting should be used, how the layout should appear, what pictures should be placed in certain locations, and more.

Two Sided Tags: Two-sided tag encloses text between opening and closing tags, in this case and . Note the forward slash in the closing tag (). That slash distinguishes an opening tag from a closing tag. With a two-sided tag, there is always a corresponding closing tag for every opening tag.

Empty Tags or One Sided Tags: Not every tag encloses document content. Empty tags or one sided tags are elements that are either non-textual (such as images) or contain directives to the browser about how the page should be treated. An empty tag is entered using one of the following forms of the one-sided tag