HTML (HyperText Markup Language): Web Development Explained
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HTML, or HyperText Markup Language, is the standard language used to create and design websites. It is a cornerstone technology, alongside CSS and JavaScript, that forms the foundation of the World Wide Web. HTML provides the structure of a webpage, while CSS styles it and JavaScript adds interactivity.
HTML is not a programming language, but rather a markup language. This means it doesn't have the ability to create dynamic functionality. Instead, it makes it possible to organize and format documents, similar to Microsoft Word. When working with HTML, we use simple code structures (tags and attributes) to mark up a website page. For example, we can create paragraphs, links, forms, and anything else we see on the internet today.
History of HTML
The history of HTML is a journey through the evolution of the web, from its inception in the early 1990s to the interactive, multimedia experience we know today. HTML was first developed by Tim Berners-Lee in 1989, while he was working at CERN, the European physics research center. The language was created to meet the need for a system that could easily share and link documents across different computers.
Since then, HTML has gone through several revisions and updates, each one adding new features and capabilities to the language. The most recent version, HTML5, was finalized and published in 2014 by the World Wide Web Consortium (W3C) and the Web Hypertext Application Technology Working Group (WHATWG). HTML5 introduced a number of new elements and attributes that reflect typical usage on modern websites.
HTML Versions
Over the years, HTML has evolved through several versions, each introducing new elements and deprecating others. The first version, HTML 1.0, was limited in its capabilities, but it laid the groundwork for what was to come. HTML 2.0, released in 1995, introduced forms, allowing for user input and interaction. HTML 3.2, released in 1997, added support for tables and other elements for presenting data.
HTML 4.01, released in 1999, introduced a host of new features, including better support for multimedia, scripts, and stylesheets. It also marked the beginning of the push towards separating content (HTML) from presentation (CSS). HTML5, the current version, was released in 2014 and introduced new elements for multimedia, graphic drawing, and better semantic support.
HTML Elements
HTML documents are made up of elements. An HTML element is defined by a start tag, some content, and an end tag. The name of the element is written inside the angle brackets. For example, the paragraph element is defined by the start tag
and the end tag
. The content of the element is everything that is between the start tag and the end tag.
There are many types of HTML elements, each with its own purpose and use. Some elements are used for structuring the content, like the
- ,
- ), tables (, ,
), and many more.
- ,
Block-level and Inline Elements
HTML elements can be divided into two categories: block-level elements and inline elements. Block-level elements form a separate block on a new line and take up the full width available. Examples of block-level elements include
-
,
, and
On the other hand, inline elements do not start on a new line and only take up as much width as necessary. Examples of inline elements include , , , and
HTML Attributes
HTML attributes provide additional information about an element. Attributes are always specified in the start tag and usually come in name/value pairs like name="value". For example, the element (which creates a hyperlink) uses the "href" attribute to specify the URL of the page the link goes to.
There are many different types of attributes, each with its own purpose. Some attributes are used for specifying characteristics of the element, like the "src" attribute for images, which specifies the source file for the image. Others are used for styling the element, like the "style" attribute, which can be used to add inline CSS to an element.
Global Attributes
Global attributes are attributes that can be used on any HTML element. These include "class", which is used to specify a class for an element; "id", which specifies a unique id for an element; "style", which is used to add inline styles to an element; and "title", which specifies extra information about an element.
Using global attributes effectively can greatly enhance the functionality and accessibility of a webpage. For example, the "alt" attribute provides alternative text for an image, which can be read by screen readers for visually impaired users, or displayed if the image fails to load.
HTML Document Structure
An HTML document has a specific structure that must be followed. At the top of the document is the declaration, which tells the browser that this is an HTML5 document. Following this is the element, which contains all the HTML code for the page.
Inside the element are two main sections: the and the . The contains meta-information about the document, such as its title and link to any CSS or JavaScript files. The contains the actual content of the webpage, such as text, images, and links.
The Head Section
The section of an HTML document is where you provide information about the document itself, rather than the content that appears on the webpage. This includes the title of the document, which appears in the browser's title bar or tab; meta tags, which can provide information about the document's character encoding, viewport settings, and more; and links to external resources like CSS stylesheets or JavaScript files.
It's important to note that while the section is essential for a properly structured HTML document, it doesn't directly contribute to what the user sees on the page. Instead, it provides important context and resources for how the page should be displayed and function.
The Body Section
The section of an HTML document is where you put the content that users see on the webpage. This can include text, images, videos, links, forms, and more. Each piece of content is marked up with HTML elements to structure and format it.
When creating the section of an HTML document, it's important to use semantic HTML elements where possible. These are elements that clearly describe their meaning in both human and machine language. For example, using the
,
HTML Forms
HTML forms are a key part of interactive websites. They allow users to input data that can be sent to a server for processing. A form can contain input elements like text fields, checkboxes, radio-buttons, submit buttons, and more. The
Each input element within a form has its own specific attributes. For example, the element's "type" attribute specifies the type of input element to display. The "name" and "value" attributes define the name and initial value for the input field. The
Form Handling
When a user fills out a form and clicks the submit button, the form data is sent to a web server for processing. This is done using the "action" attribute on the
The "GET" method appends the form data to the URL in name/value pairs, and is suitable for small amounts of data. The "POST" method sends the form data as an HTTP post transaction, and is used for large amounts of data or sensitive data like passwords. Understanding how to handle form data securely and efficiently is a key part of web development.
HTML and CSS
While HTML provides the structure of a webpage, CSS (Cascading Style Sheets) is used to style the HTML elements on the page. CSS can control aspects like layout, color, fonts, and more. CSS can be included in an HTML document in three ways: inline, internal, and external.
Inline styles are applied directly to the HTML element using the "style" attribute. Internal styles are defined in the section of the HTML document inside.