How to select element by 'role' attribute and filter by class with vanilla JS?

Question

Markup:

  

    How to Install for iPad         


        

Answer 1

var eleLi = document.querySelectorAll('[role="presentation"]');  
for (var i = 0; i < eleLi.length; i++) {
    //remove class active
    eleLi[i].classList.remove('active');
}

//x is an index of li that you want to add the class. Such as 0,1,2
var x = eleLi.length - 1;

//add class active
eleLi[x].classList.add('active');