jQuery change class name

Using jQuery You can set the class (regardless of what it was) by using .attr(), like this:

$("#td_id").attr('class', 'newClass');

If you want to add a class, use .addclass() instead, like this:

$("#td_id").addClass('newClass');

Or a short way to swap classes using .toggleClass():

$("#td_id").toggleClass('change_me newClass');

Here's the full list of jQuery methods specifically for the class attribute.

I think you're looking for this:

$('#td_id').removeClass('change_me').addClass('new_class');

I think he wants to replace a class name.

Something like this would work:

$(document).ready(function(){
    $('.blue').removeClass('blue').addClass('green');
});

from http://monstertut.com/2012/06/use-jquery-to-change-css-class/