What is a Web Worker?

A web worker is a JavaScript running in the background, without affecting the performance of the page.
When executing scripts in an HTML page, the page becomes unresponsive until the script is finished.
A web worker is a JavaScript that runs in the background, independently of other scripts, without affecting the performance of the page. You can continue to do whatever you want: clicking, selecting things, etc., while the web worker runs in the background.


Toggle the visibility of content across your project with a few classes and our JavaScript plugins. 0453269453


Examples and usage guidelines for form control styles, layout options, and custom components for creating a wide variety of forms.



Documentation and examples for adding Bootstrap popovers, like those found in iOS, to any element on your site.

Screen readers

Use screen reader utilities to hide elements on all devices except screen readers. 0453269453

Stretched link

Make any HTML element or Bootstrap component clickable by “stretching” a nested link via CSS.


Related Content


HTML Video How it Works
The controls attribute adds video controls, like play, pause, and volume.
It is a good idea to always include width and height attributes. If height and width are not set, the page might flicker while the video loads.
The source element allows you to specify alternative video files which the browser may choose from. The browser will use the first recognized format.
The text between the video tags will only be displayed in browsers that do not support the video element.


Design for Mobile First Always Design for Mobile First
Mobile First means designing for mobile before designing for desktop or any other device (This will make the page display faster on smaller devices).
This means that we must make some changes in our CSS.
Instead of changing styles when the width gets smaller than 768px, we should change the design when the width gets larger than 768px. This will make our design Mobile First:


State and Lifecycle This page introduces the concept of state and lifecycle in a React component. You can find a detailed component API reference here.
Consider the ticking clock example from one of the previous sections. In Rendering Elements, we have only learned one way to update the UI. We call ReactDOM.render() to change the rendered output:


Using Emojis Emojis are characters from the UTF-8 character set: 😄 😍 💗
What are Emojis?
Emojis look like images, or icons, but they are not.
They are letters (characters) from the UTF-8 (Unicode) alphabet.
UTF-8 covers almost all of the characters and symbols in the world.
The HTML charset Attribute
To display an HTML page correctly, a web browser must know the character set used in the page.
This is specified in the meta tag:


Bootstrap Build responsive, mobile-first projects on the web with the world’s most popular front-end component library.
Bootstrap is an open source toolkit for developing with HTML, CSS, and JS. Quickly prototype your ideas or build your entire app with our Sass variables and mixins, responsive grid system, extensive prebuilt components, and powerful plugins built on jQuery.


What is HTML? HTML stands for Hyper Text Markup Language
HTML describes the structure of a Web page
HTML consists of a series of elements
HTML elements tell the browser how to display the content
HTML elements are represented by tags
HTML tags label pieces of content such as "heading", "paragraph", "table", and so on
Browsers do not display the HTML tags, but use them to render the content of the page