apply css from js code example

Example 1: how to give css style in javascript

document.getElementById("myH1").style.color = "red";

Example 2: css in js

JSS is an authoring tool for CSS which allows you to use JavaScript to describe styles in a declarative, conflict-free and reusable way. It can compile in the browser, server-side or at build time in Node.

JSS is framework agnostic. It consists of multiple packages: the core, plugins, framework integrations and others.