javascript get css custom property code example

Example 1: access css property using javascript

const element = document.querySelector('.element')
const style = getComputedStyle(element)

Example 2: javascript use css custom properties

Values in JavaScript
To use the values of custom properties in JavaScript, it is just like standard properties.
// get variable from inline style
element.style.getPropertyValue("--my-var");

// get variable from wherever
getComputedStyle(element).getPropertyValue("--my-var");

// set variable on inline style
element.style.setProperty("--my-var", jsVar + 4);