Here is an example to show how you can include an external JavaScript file in your HTML code using script tag and its src attribute. The script tag provides a mechanism to allow you to store JavaScript in an external file and then include it into your HTML files. You are not restricted to be maintaining identical code in multiple HTML files. It also allows React to show more useful error and warning messages.This code will produce the following result − JavaScript in External FileĪs you begin to work more extensively with JavaScript, you will be likely to find that there are cases where you are reusing identical JavaScript code on multiple pages of a site. React doesn’t require using JSX, but most people find it helpful as a visual aid when working with UI inside the JavaScript code. We will come back to components in a further section, but if you’re not yet comfortable putting markup in JS, this talk might convince you otherwise.

Instead of artificially separating technologies by putting markup and logic in separate files, React separates concerns with loosely coupled units called “components” that contain both. React embraces the fact that rendering logic is inherently coupled with other UI logic: how events are handled, how the state changes over time, and how the data is prepared for display. Below, you can find the basics of JSX necessary to get you started.

We will explore rendering them to the DOM in the next section. JSX may remind you of a template language, but it comes with the full power of JavaScript.

We recommend using it with React to describe what the UI should look like. It is called JSX, and it is a syntax extension to JavaScript. This funny tag syntax is neither a string nor HTML.

Include javascript in html