HTML (HyperText Markup Language) is the most basic building block of the Web. It defines the meaning and structure of web content. Other technologies besides HTML are generally used to describe a web page's appearance/presentation (CSS) or functionality/behavior (JavaScript).
"Hypertext" refers to links that connect web pages to one another, either within a single website or between websites. Links are a fundamental aspect of the Web. By uploading content to the Internet and linking it to pages created by other people, you become an active participant in the World Wide Web.
HTML uses "markup" to annotate text, images, and other content for display in a Web browser. HTML markup includes special "elements" such as <head>, <title>, <body>, <header>, <footer>, <article>, <section>, <p>, <div>, <span>, <img>, <aside>, <audio>, <canvas>, <datalist>, <details>, <embed>, <nav>, <search>, <output>, <progress>, <video>, <ul>, <ol>, <li> and many others.
An HTML element is set off from other text in a document by "tags", which consist of the element name surrounded by < and >. The name of an element inside a tag is case-insensitive. That is, it can be written in uppercase, lowercase, or a mixture. For example, the <title> tag can be written as <Title>, <TITLE>, or in any other way. However, the convention and recommended practice is to write tags in lowercase.
The articles below can help you learn more about HTML.
The HTML guides help you build with HTML on the web, covering topics such as forms, CORS, content preloading, and responsive images.
- HTML forms
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Forms are a very important part of the Web — these provide much of the functionality you need for interacting with websites, e.g., registering and logging in, sending feedback, buying products, and more. This module gets you started with creating the client-side/front-end parts of forms.
- CORS enabled image
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The crossorigin attribute, in combination with an appropriate CORS header, allows images defined by the <img> element to be loaded from foreign origins and used in a <canvas> element as if they were being loaded from the current origin.
- CORS settings attributes
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Some HTML elements that provide support for CORS, such as <img> or <video>, have a crossorigin attribute (crossOrigin property), which lets you configure the CORS requests for the element's fetched data.
- Preloading content with rel="preload"
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The preload value of the <link> element's rel attribute allows you to write declarative fetch requests in your HTML <head>, specifying resources that your pages will need very soon after loading, which you therefore want to start preloading early in the lifecycle of a page load, before the browser's main rendering machinery kicks in. This ensures that they are made available earlier and are less likely to block the page's first render, leading to performance improvements. This article provides a basic guide to how preload works.
- Responsive images
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In this article, we'll learn about the concept of responsive images — images that work well on devices with widely differing screen sizes, resolutions, and other such features — and look at what tools HTML provides to help implement them. This helps to improve performance across different devices.