js set class
var element = document.getElementById('element'); element.classList.add('class-1'); element.classList.add('class-2', 'class-3'); element.classList.remove('class-3');
Javascript change element class
document.getElementById("myElementID").classList.add('myClassName'); document.getElementById("myElementID").classList.remove('myClassName');
javascript change element class
//Overwrite all classes element.className = "class"; //Add class element.classList.add("class");
javascript change class name
function switchMode(){ // Body switching if(document.getElementById("page-body").className == "page-body-day"){ document.getElementById("page-body").className = "page-body-night"; }else{ document.getElementById("page-body").className = "page-body-day"; } // Heading switching if(document.getElementById("main-heading").className == "main-heading-day"){ document.getElementById("main-heading").className = "main-heading-night"; }else{ document.getElementById("main-heading").className = "main-heading-day"; } }
Source: stackabuse.com