change css variables with javascript code example

Example 1: how to change a css variable with javascript

var root = document.querySelector(':root');
root.style.setProperty('--variable', 'lightblue');
/or/
root.style.setProperty('--variable', myColor);

Example 2: javascript get css variable

let docStyle = getComputedStyle(document.documentElement);

//get variable
let myVarVal docStyle.getPropertyValue('--my-variable-name');

//set variable
docStyle.setProperty('--my-variable-name', '#fff');

Example 3: how to change css variable in javascript

document.documentElement.style.setProperty("--main-background-color", "green");

Example 4: set css variable from javascript

document.documentElement.style.cssText = "--tab-count: 3";
/or/
document.documentElement.style.setProperty("--tab-count", 5);
/or/
document.documentElement.setAttribute("style", "--tab-count: 5");

Example 5: how to change css variable in javascript

document.documentElement.setAttribute("style", "--main-background-color: green");

Example 6: how to change css variable in javascript

document.documentElement.style.cssText = "--main-background-color: red";