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.

Child Elements

A grid container contains grid items.
By default, a container has one grid item for each column, in each row, but you can style the grid items so that they will span multiple columns and or rows. 033151331


Documentation and examples for showing pagination to indicate a series of related content exists across multiple pages.



Bootstrap includes a wide range of shorthand responsive margin and padding utility classes to modify an element’s appearance.

What Are We Building?

In this tutorial, we’ll show how to build an interactive tic-tac-toe game with React.
You can see what we’ll be building here: Final Result. If the code doesn’t make sense to you, or if you are unfamiliar with the code’s syntax, don’t worry! The goal of this tutorial is to help you understand React and its syntax.
We recommend that you check out the tic-tac-toe game before continuing with the tutorial. One of the features that you’ll notice is that there is a numbered list to the right of the game’s board. This list gives you a history of all of the moves that have occurred in the game, and it is updated as the game progresses.
You can close the tic-tac-toe game once you’re familiar with it. We’ll be starting from a simpler template in this tutorial. Our next step is to set you up so that you can start building the game. 033151331

What Is React?

React is a declarative, efficient, and flexible JavaScript library for building user interfaces.
It lets you compose complex UIs from small and isolated pieces of code called “components”. React has a few different kinds of components, but we’ll start with React.Component subclasses:


Related Content


Dropdowns Toggle contextual overlays for displaying lists of links and more with the Bootstrap dropdown plugin.


The Viewport What is The Viewport?
The viewport is the user visible area of a web page.
The viewport varies with the device, and will be smaller on a mobile phone than on a computer screen.
Before tablets and mobile phones, web pages were designed only for computer screens, and it was common for web pages to have a static design and a fixed size.
Then, when we started surfing the internet using tablets and mobile phones, fixed size web pages were too large to fit the viewport.
To fix this, browsers on those devices scaled down the entire web page to fit the screen. This was not perfect!! But a quick fix.


List group List groups are a flexible and powerful component for displaying a series of content. Modify and extend them to support just about any content within.


Flex Quickly manage the layout, alignment, and sizing of grid columns, navigation, components, and more with a full suite of responsive flexbox utilities. For more complex implementations, custom CSS may be necessary.


Paragraphs A paragraph always starts on a new line, and browsers automatically add some white space (a margin) before and after a paragraph.


Borders Use border utilities to quickly style the border and border-radius of an element. Great for images, buttons, or any other element.