Select and add class in javascript

Question

Cross Platform if possible, how can I select classes in Javascript (but not Jquery please -MooTools is fine though-) on code that I can\'t add an ID? Specifically, I want to add

Answer 1

As others mention for selecting the elements you should use .querySelectorAll() method. DOM also provides classList API which supports adding, removing and toggling classes:

var list, i;
list = document.querySelectorAll('.even, .foo');
for (i = 0; i < list.length; i++) {
    list[i].classList.add('cf');
}

As always IE9 and bellow don't support the API, if you want to support those browsers you can use a shim, MDN has one.