HTML Basics

HTML (HyperText Markup Language) is the code that is used to structure a web page and its content. For example, content could be structured within a set of paragraphs, a list of bulleted points, or using images and data tables. As the title suggests, this article will give you a basic understanding of HTML and its functions.

So what is HTML?

HTML is a markup language that defines the structure of your content. HTML consists of a series of elements, which you use to enclose, or wrap, different parts of the content to make it appear a certain way, or act a certain way. The enclosing tags can make a word or image hyperlink to somewhere else, can italicize words, can make the font bigger or smaller, and so on. For example, take the following line of content:

If we wanted the line to stand by itself, we could specify that it is a paragraph by enclosing it in paragraph tags:

Anatomy of an HTML element

Let's explore this paragraph element a bit further.

The main parts of our element are as follows:

The opening tag: This consists of the name of the element (in this case, p), wrapped in opening and closing angle brackets. This states where the element begins or starts to take effect — in this case where the paragraph begins.
The closing tag: This is the same as the opening tag, except that it includes a forward slash before the element name. This states where the element ends — in this case where the paragraph ends. Failing to add a closing tag is one of the standard beginner errors and can lead to strange results.
The content: This is the content of the element, which in this case, is just text.
The element: The opening tag, the closing tag, and the content together comprise the element.

Elements can also have attributes that look like the following:

Attributes contain extra information about the element that you don't want to appear in the actual content. Here, <class> is the attribute name and editor-note is the attribute value. The <class> attribute allows you to give the element a non-unique identifier that can be used to target it (and any other elements with the same <class> value) with style information and other things. Some attributes have no value, such as required.

Attributes that set a value always have:

A space between it and the element name (or the previous attribute, if the element already has one or more attributes).
The attribute name followed by an equal sign.
The attribute value wrapped by opening and closing quotation marks.

Nesting Elements

You can put elements inside other elements too — this is called nesting. If we wanted to state that our cat is very grumpy, we could wrap the word "very" in a <strong> element, which means that the word is to be strongly emphasized:

You do however need to make sure that your elements are properly nested. In the example above, we opened the <p> element first, then the <strong> element; therefore, we have to close the <strong> element first, then the <p> element. The following is incorrect:

The elements have to open and close correctly so that they are clearly inside or outside one another. If they overlap as shown above, then your web browser will try to make the best guess at what you were trying to say, which can lead to unexpected results. So don't do it!

Void Elements

Some elements have no content and are called void elements. Take the <img> element that we already have in our HTML page:

This contains two attributes, but there is no closing </img> tag and no inner content. This is because an image element doesn't wrap content to affect it. Its purpose is to embed an image in the HTML page in the place it appears.

Anatomy of an HTML Document

That wraps up the basics of individual HTML elements, but they aren't handy on their own. Now we'll look at how individual elements are combined to form an entire HTML page.

Here, we have the following:

<!DOCTYPE html> — doctype. It is a required preamble. In the mists of time, when HTML was young (around 1991/92), doctypes were meant to act as links to a set of rules that the HTML page had to follow to be considered good HTML, which could mean automatic error checking and other useful things. However, these days, they don't do much and are basically just needed to make sure your document behaves correctly. That's all you need to know for now.
<html></html> — the <html> element. This element wraps all the content on the entire page and is sometimes known as the root element. It also includes the lang attribute, setting the primary language of the document.
<head></head> — the <head> element. This element acts as a container for all the stuff you want to include on the HTML page that isn't the content you are showing to your page's viewers. This includes things like keywords and a page description that you want to appear in search results, CSS to style our content, character set declarations, and more.
<meta charset="utf-8"> — This element sets the character set your document should use to UTF-8 which includes most characters from the vast majority of written languages. Essentially, it can now handle any textual content you might put on it. There is no reason not to set this, and it can help avoid some problems later on.
<meta name="viewport" content="width=device-width"> — This viewport element ensures the page renders at the width of viewport, preventing mobile browsers from rendering pages wider than the viewport and then shrinking them down.
<title></title> — the <title> element. This sets the title of your page, which is the title that appears in the browser tab the page is loaded in. It is also used to describe the page when you bookmark/favorite it.
<body></body> — the <body> element. This contains all the content that you want to show to web users when they visit your page, whether that's text, images, videos, games, playable audio tracks, or whatever else.

<a> The Anchor element

The <a> HTML element (or anchor element), with its href attribute, creates a hyperlink to web pages, files, email addresses, locations in the same page, or anything else a URL can address. Content within each <a> should indicate the link's destination. If the href attribute is present, pressing the enter key while focused on the <a> element will activate it.

<abbr> The Abbreviation element

The <abbr> HTML element represents an abbreviation or acronym. When including an abbreviation or acronym, provide a full expansion of the term in plain text on first use, along with the <abbr> to mark up the abbreviation. This informs the user what the abbreviation or acronym means. The optional title attribute can provide an expansion for the abbreviation or acronym when a full expansion is not present. This provides a hint to user agents on how to announce/display the content while informing all users what the abbreviation means. If present, title must contain this full description and nothing else.

<address> The Address element

The <address> HTML element indicates that the enclosed HTML provides contact information for a person or people, or for an organization.

<area> The Image Map Area element

The <area> HTML element defines an area inside an image map that has predefined clickable areas. An image map allows geometric areas on an image to be associated with hypertext links. This element is used only within a <map> element.

<article> The Article Contents element

The <article> HTML element represents a self-contained composition in a document, page, application, or site, which is intended to be independently distributable or reusable (e.g., in syndication). Examples include: a forum post, a magazine or newspaper article, or a blog entry, a product card, a user-submitted comment, an interactive widget or gadget, or any other independent item of content.

<aside> The Aside element

The <aside> HTML element represents a portion of a document whose content is only indirectly related to the document's main content. Asides are frequently presented as sidebars or call-out boxes.

<audio> The Embed Audio element

The <audio> HTML element is used to embed sound content in documents. It may contain one or more audio sources, represented using the src attribute or the <source> element: the browser will choose the most suitable one. It can also be the destination for streamed media, using a MediaStream.

<b> The Bring Attention To element

The <b> HTML element is used to draw the reader's attention to the element's contents, which are not otherwise granted special importance. This was formerly known as the Boldface element, and most browsers still draw the text in boldface. However, you should not use <b> for styling text or granting importance. If you wish to create boldface text, you should use the CSS font-weight property. If you wish to indicate an element is of special importance, you should use the <strong> element.

<base> The Document Base URL element

The <base> HTML element specifies the base URL to use for all relative URLs in a document. There can be only one <base> element in a document.

<bdi> The Bidirectional Isolate element

The <bdi> HTML element tells the browser's bidirectional algorithm to treat the text it contains in isolation from its surrounding text. It's particularly useful when a website dynamically inserts some text and doesn't know the directionality of the text being inserted.

<bdo> The Bidirectional Text Override element

The <bdo> HTML element overrides the current directionality of text, so that the text within is rendered in a different direction.

<blockquote> The Block Quotation element

The <blockquote> HTML element indicates that the enclosed text is an extended quotation. Usually, this is rendered visually by indentation (see Notes for how to change it). A URL for the source of the quotation may be given using the cite attribute, while a text representation of the source can be given using the <cite> element.

<body> The Document Body element

The <body> HTML element represents the content of an HTML document. There can be only one <body> element in a document.

<br> The Line Break element

The <br> HTML element produces a line break in text (carriage-return). It is useful for writing a poem or an address, where the division of lines is significant.

<button> The Button element

The <button> HTML element is an interactive element activated by a user with a mouse, keyboard, finger, voice command, or other assistive technology. Once activated, it then performs an action, such as submitting a form or opening a dialog. By default, HTML buttons are presented in a style resembling the platform the user agent runs on, but you can change buttons' appearance with CSS.

<canvas> The Graphics Canvas element

Use the HTML <canvas> element with either the canvas scripting API or the WebGL API to draw graphics and animations.

<caption> The Table Caption element

The <caption> HTML element specifies the caption (or title) of a table.

<cite> The Citation element

The <cite> HTML element is used to mark up the title of a cited creative work. The reference may be in an abbreviated form according to context-appropriate conventions related to citation metadata.

<code> The Inline Code element

The <code> HTML element displays its contents styled in a fashion intended to indicate that the text is a short fragment of computer code. By default, the content text is displayed using the user agent's default monospace font.

<col> The Table Column element

The <col> HTML element defines a column within a table and is used for defining common semantics on all common cells. It is generally found within a <colgroup> element.

<colgroup> The Table Column Group element

The <colgroup> HTML element defines a group of columns within a table.

<data> The Data element

The <data> HTML element links a given piece of content with a machine-readable translation. If the content is time- or date-related, the <time> element must be used.

<datalist> The Data element

The <datalist> HTML element contains a set of <option> elements that represent the permissible or recommended options available to choose from within other controls.

<dd> The Description Details element

The <dd> HTML element provides the description, definition, or value for the preceding term (<dt>) in a description list (<dl>).

<del> The Deleted Text element

The <del> HTML element represents a range of text that has been deleted from a document. This can be used when rendering "track changes" or source code diff information, for example. The <ins> element can be used for the opposite purpose: to indicate text that has been added to the document.

<details> The Details disclosure element

The <details> HTML element creates a disclosure widget in which information is visible only when the widget is toggled into an "open" state. A summary or label must be provided using the <summary> element. A disclosure widget is typically presented onscreen using a small triangle which rotates (or twists) to indicate open/closed status, with a label next to the triangle. The contents of the <summary> element are used as the label for the disclosure widget.

<dfn> The Definition element

The <dfn> HTML element is used to indicate the term being defined within the context of a definition phrase or sentence. The ancestor <p> element, the <dt>/<dd> pairing, or the nearest <section> ancestor of the <dfn> element, is considered to be the definition of the term.

<dialog> The Dialog element

The <dialog> HTML element represents a modal or non-modal dialog box or other interactive component, such as a dismissible alert, inspector, or subwindow. The HTML <dialog> element is used to create both modal and non-modal dialog boxes. Modal dialog boxes interrupt interaction with the rest of the page being inert, while non-modal dialog boxes allow interaction with the rest of the page.

<div> The Content Division element

The <div> HTML element is the generic container for flow content. It has no effect on the content or layout until styled in some way using CSS (e.g. styling is directly applied to it, or some kind of layout model like Flexbox is applied to its parent element).

<dl> The Description List element

The <dl> HTML element represents a description list. The element encloses a list of groups of terms (specified using the <dt> element) and descriptions (provided by <dd> elements). Common uses for this element are to implement a glossary or to display metadata (a list of key-value pairs).

<dt> The Description Term element

The <dt> HTML element specifies a term in a description or definition list, and as such must be used inside a <dl> element. It is usually followed by a <dd> element; however, multiple <dt> elements in a row indicate several terms that are all defined by the immediate next <dd> element. The subsequent <dd> (Description Details>) element provides the definition or other related text associated with the term specified using <dt>.

<em> The Emphasis element

The <em> HTML element marks text that has stress emphasis. The <em> element can be nested, with each level of nesting indicating a greater degree of emphasis.

<embed> The Embed External Content element

The <embed> HTML element embeds external content at the specified point in the document. This content is provided by an external application or other source of interactive content such as a browser plug-in.

<fieldset> The Field Set element

The <fieldset> HTML element is used to group several controls as well as labels (<label>) within a web form.

<figcaption> The Figure Caption element

The <figcaption> HTML element represents a caption or legend describing the rest of the contents of its parent <figure> element.

<figure> The Figure with Optional Caption element

The <figure> HTML element represents self-contained content, potentially with an optional caption, which is specified using the <figcaption> element. The figure, its caption, and its contents are referenced as a single unit.

The <footer> HTML element represents a footer for its nearest ancestor sectioning content or sectioning root element. A <footer> typically contains information about the author of the section, copyright data or links to related documents.

<form> The Form element

The <form> HTML element represents a document section containing interactive controls for submitting information.

<h1> - <h6> The HTML Section Heading element

The <h1> to <h6> HTML elements represent six levels of section headings. <h1> is the highest section level and <h6> is the lowest. By default, all heading elements create a block-level box in the layout, starting on a new line and taking up the full width available in their containing block.

<head> The Document Metadata (Header) element

The <head> HTML element contains machine-readable information (metadata) about the document, like its title, scripts, and style sheets.

The <header> HTML element represents introductory content, typically a group of introductory or navigational aids. It may contain some heading elements but also a logo, a search form, an author name, and other elements.

<hgroup> The Heading Group element

The <hgroup> HTML element represents a heading and related content. It groups a single <h1> – <h6> element with one or more <p>.

<hr> The Thematic Break (Horizontal Rule) element

The <hr> HTML element represents a thematic break between paragraph-level elements: for example, a change of scene in a story, or a shift of topic within a section.

<html> The HTML Document / Root element

The <html> HTML element represents the root (top-level element) of an HTML document, so it is also referred to as the root element. All other elements must be descendants of this element.

<i> The Idiomatic Text element

The <i> HTML element represents a range of text that is set off from the normal text for some reason, such as idiomatic text, technical terms, taxonomical designations, among others. Historically, these have been presented using italicized type, which is the original source of the <i> naming of this element.

<iframe> The Inline Frame element

The <iframe> HTML element represents a nested browsing context, embedding another HTML page into the current one.

<img> The Image Embed element

The <img> HTML element embeds an image into the document.

<input> The Input (Form Input) element

The <input> HTML element is used to create interactive controls for web-based forms in order to accept data from the user; a wide variety of types of input data and control widgets are available, depending on the device and user agent. The <input> element is one of the most powerful and complex in all of HTML due to the sheer number of combinations of input types and attributes.

<ins> The Inserted Text element

The <ins> HTML element represents a range of text that has been added to a document. You can use the <del> element to similarly represent a range of text that has been deleted from the document.

<kbd> The Keyboard Input element

The <kbd> HTML element represents a span of inline text denoting textual user input from a keyboard, voice input, or any other text entry device. By convention, the user agent defaults to rendering the contents of a <kbd> element using its default monospace font, although this is not mandated by the HTML standard.

<label> The Label element

The <label> HTML element represents a caption for an item in a user interface.

<legend> The Field Set Legend element

The <legend> HTML element represents a caption for the content of its parent <fieldset>.

<li> The List Item element

The <li> HTML element is used to represent an item in a list. It must be contained in a parent element: an ordered list (<ol>), an unordered list (<ul>), or a menu (<menu>). In menus and unordered lists, list items are usually displayed using bullet points. In ordered lists, they are usually displayed with an ascending counter on the left, such as a number or letter.

<link> The External Resource Link element

The <link> HTML element specifies relationships between the current document and an external resource. This element is most commonly used to link to stylesheets, but is also used to establish site icons (both "favicon" style icons and icons for the home screen and apps on mobile devices) among other things.

<main> The Main element

The <link> HTML element represents the dominant content of the <body> of a document. The main content area consists of content that is directly related to or expands upon the central topic of a document, or the central functionality of an application.

<map> The Image Map element

The <map> HTML element is used with <area> elements to define an image map (a clickable link area).

<mark> The Mark Text element

The <mark> HTML element represents text which is marked or highlighted for reference or notation purposes due to the marked passage's relevance in the enclosing context.

The <menu> HTML element is described in the HTML specification as a semantic alternative to <ul>, but treated by browsers (and exposed through the accessibility tree) as no different than <ul>. It represents an unordered list of items (which are represented by <li> elements).

<meta> The Metadata element

The <meta> HTML element represents metadata that cannot be represented by other HTML meta-related elements, like <base>, <link>, <script>, <style> or <title>.

<meter> The HTML Meter element

The <meter> HTML element represents either a scalar value within a known range or a fractional value.

<nav> The Navigation Section element

The <nav> HTML element represents a section of a page whose purpose is to provide navigation links, either within the current document or to other documents. Common examples of navigation sections are menus, tables of contents, and indexes.

<noscript> The Noscript element

The <noscript> HTML element defines a section of HTML to be inserted if a script type on the page is unsupported or if scripting is currently turned off in the browser.

<object> The External Object element

The <object> HTML element represents an external resource, which can be treated as an image, a nested browsing context, or a resource to be handled by a plugin.

<ol> The Ordered List element

The <ol> HTML element represents an ordered list of items — typically rendered as a numbered list.

<optgroup> The Option Group element

The <optgroup> HTML element creates a grouping of options within a <select> element.

<option> The HTML Option element

The <option> HTML element is used to define an item contained in a <select><code>, an <optgroup>, or a <datalist> element. As such, <option> can represent menu items in popups and other lists of items in an HTML document.

<output> The Output element

The <output> HTML element is a container element into which a site or app can inject the results of a calculation or the outcome of a user action.

<p> The Paragraph element

The <p> HTML element represents a paragraph. Paragraphs are usually represented in visual media as blocks of text separated from adjacent blocks by blank lines and/or first-line indentation, but HTML paragraphs can be any structural grouping of related content, such as images or form fields. Paragraphs are block-level elements, and notably will automatically close if another block-level element is parsed before the closing </p> tag.

<picture> The Picture element

The <picture> HTML element contains zero or more <source> elements and one <img> element to offer alternative versions of an image for different display/device scenarios. The browser will consider each child <source> element and choose the best match among them. If no matches are found—or the browser doesn't support the <picture> element—the URL of the <img> element's src attribute is selected. The selected image is then presented in the space occupied by the <img> element.

<pre> The Preformatted Text element

The <pre> HTML element represents preformatted text which is to be presented exactly as written in the HTML file. The text is typically rendered using a non-proportional, or monospaced, font. Whitespace inside this element is displayed as written. By default, <pre> is a block-level element, i.e. its default display value is block.

<progress> The Progress Indicator element

The <progress> HTML element displays an indicator showing the completion progress of a task, typically displayed as a progress bar.

<q> The Inline Quotation element

The <q> HTML element indicates that the enclosed text is a short inline quotation. Most modern browsers implement this by surrounding the text in quotation marks. This element is intended for short quotations that don't require paragraph breaks; for long quotations use the <blockquote> element.

<rp> The Ruby Fallback Parenthesis element

The <rp> HTML element is used to provide fall-back parentheses for browsers that do not support display of ruby annotations using the <ruby> element. One <rp> element should enclose each of the opening and closing parentheses that wrap the <rt> element that contains the annotation's text.

<rt> The Ruby Text element

The <rt> HTML element specifies the ruby text component of a ruby annotation, which is used to provide pronunciation, translation, or transliteration information for East Asian typography. The <rt> element must always be contained within a <ruby> element.

<ruby> The Ruby Annotation element

The <ruby> HTML element represents small annotations that are rendered above, below, or next to base text, usually used for showing the pronunciation of East Asian characters. It can also be used for annotating other kinds of text, but this usage is less common. The term ruby originated as a unit of measurement used by typesetters, representing the smallest size that text can be printed on newsprint while remaining legible.

<s> The Strikethrough element

The <s> HTML element renders text with a strikethrough, or a line through it. Use the <s> element to represent things that are no longer relevant or no longer accurate. However, <s> is not appropriate when indicating document edits; for that, use the <del> and <ins> elements, as appropriate.

<samp> The Sample Output element

The <samp> HTML element is used to enclose inline text which represents sample (or quoted) output from a computer program. Its contents are typically rendered using the browser's default monospaced font (such as Courier or Lucida Console).

<script> The Script element

The <script> HTML element is used to embed executable code or data; this is typically used to embed or refer to JavaScript code. The <script> element can also be used with other languages, such as WebGL's GLSL shader programming language and JSON.

<search> The Generic Search element

The <search> HTML element is a container representing the parts of the document or application with form controls or other content related to performing a search or filtering operation. The <search> element semantically identifies the purpose of the element's contents as having search or filtering capabilities. The search or filtering functionality can be for the website or application, the current web page or document, or the entire Internet or subsection thereof.

<section> The Generic Section element

The <section> HTML element represents a generic standalone section of a document, which doesn't have a more specific semantic element to represent it. Sections should always have a heading, with very few exceptions.

<select> The HTML Select element

The <select> HTML element represents a control that provides a menu of options.

<slot> The Web Component Slot element

The <slot> HTML element—part of the Web Components technology suite—is a placeholder inside a web component that you can fill with your own markup, which lets you create separate DOM trees and present them together.

<small> The Side Comment element

The <small> HTML element represents side-comments and small print, like copyright and legal text, independent of its styled presentation. By default, it renders text within it one font-size smaller, such as from small to x-small.

<source> The Media or Image Source element

The <source> HTML element specifies one or more media resources for the <picture>, </code>, <audio>, and <video> elements. It is a void element, which means that it has no content and does not require a closing tag. This element is commonly used to offer the same media content in multiple file formats in order to provide compatibility with a broad range of browsers given their differing support for image file formats and media file formats.

<span> The Content Span element

The <span> HTML element is a generic inline container for phrasing content, which does not inherently represent anything. It can be used to group elements for styling purposes (using the class or id attributes), or because they share attribute values, such as lang. It should be used only when no other semantic element is appropriate. <span> is very much like a <div> element, but

is a block-level element whereas a <span> is an inline-level element.

<strong> The Strong Importance element

The <strong> HTML element indicates that its contents have strong importance, seriousness, or urgency. Browsers typically render the contents in bold type.

<style> The Style Information element

The <style> HTML element contains style information for a document, or part of a document. It contains CSS, which is applied to the contents of the document containing the <style> element.

<sub> The Subscript element

The <sub> HTML element specifies inline text which should be displayed as subscript for solely typographical reasons. Subscripts are typically rendered with a lowered baseline using smaller text.

<summary> The Disclosure Summary element

The <summary> HTML element specifies a summary, caption, or legend for a <details> element's disclosure box. Clicking the <summary> element toggles the state of the parent <details> element open and closed.

<sup> The Superscript element

The <sup> HTML element specifies inline text which is to be displayed as superscript for solely typographical reasons. Superscripts are usually rendered with a raised baseline using smaller text.

<table> The Table element

The <table> HTML element represents tabular data — that is, information presented in a two-dimensional table comprised of rows and columns of cells containing data.

<tbody> The Table Body element

The <tbody> HTML element encapsulates a set of table rows (<tr> elements), indicating that they comprise the body of the table (<table>).

<td> The Table Data Cell element

The <td> HTML element defines a cell of a table that contains data. It participates in the table model.

<template> The Content Template element

The <template> HTML element is a mechanism for holding HTML that is not to be rendered immediately when a page is loaded but may be instantiated subsequently during runtime using JavaScript. Think of a template as a content fragment that is being stored for subsequent use in the document. While the parser does process the contents of the <template> element while loading the page, it does so only to ensure that those contents are valid; the element's contents are not rendered, however.

<textarea> The Textarea element

The <textarea> HTML element represents a multi-line plain-text editing control, useful when you want to allow users to enter a sizeable amount of free-form text, for example a comment on a review or feedback form.

<tfoot> The Table Foot element

The <tfoot> HTML element defines a set of rows summarizing the columns of the table.

<th> The Table Header element

The <th> HTML element defines a cell as the header of a group of table cells. The exact nature of this group is defined by the scope and headers attributes.

<thead> The Table Head element

The <thead> HTML element defines a set of rows defining the head of the columns of the table.

<time> The (Date) Time element

The <time> HTML element represents a specific period in time. It may include the datetime attribute to translate dates into machine-readable format, allowing for better search engine results or custom features such as reminders. It may represent one of the following:

A time on a 24-hour clock.
A precise date in the Gregorian calendar (with optional time and timezone information).
A valid time duration.

<title> The Document Title element

The <title> HTML element defines the document's title that is shown in a browser's title bar or a page's tab. It only contains text; tags within the element are ignored.

<tr> The Table Row element

The <tr> HTML element defines a row of cells in a table. The row's cells can then be established using a mix of <td> (data cell) and <th> (header cell) elements.

<track> The Embed Text Track element

The <track> HTML element is used as a child of the media elements, <audio> and <video>. It lets you specify timed text tracks (or time-based data), for example to automatically handle subtitles. The tracks are formatted in WebVTT format (.vtt files) — Web Video Text Tracks.

<u> The Unarticulated Annotation (Underline) element

The <u> HTML element represents a span of inline text which should be rendered in a way that indicates that it has a non-textual annotation. This is rendered by default as a simple solid underline, but may be altered using CSS.

<ul> The Unordered List element

The <ul> HTML element represents an unordered list of items, typically rendered as a bulleted list.

<var> The Variable element

The <var> HTML element represents the name of a variable in a mathematical expression or a programming context. It's typically presented using an italicized version of the current typeface, although that behavior is browser-dependent.

<video> The Video Embed element

The <video> HTML element embeds a media player which supports video playback into the document. You can use <video> for audio content as well, but the <audio> element may provide a more appropriate user experience.

<wbr> The Line Break Opportunity element

The <wbr> HTML element represents a word break opportunity—a position within text where the browser may optionally break a line, though its line-breaking rules would not otherwise create a break at that location.