[jquery] how to change class name of an element by jquery

<div class="bestAnswerControl">
    <div id="ct100_contentplaceholder_lvanswer_control_divbestanswer"  
         class="IsBestAnswer"></div>
</div>

I want to add:

.bestanswer
{
    // some attribute
}

I want to replace class="IsBestAnswer" of div to class="bestanswer" by jquery. How do I do this?

I am using this approach:

$('.IsBestAnswer').addclass('bestanswer'); 

but it's not working.

Instead of removeClass and addClass, you can also do it like this:

$('.IsBestAnswer').toggleClass('IsBestAnswer bestanswer');

$('.IsBestAnswer').removeClass('IsBestAnswer').addClass('bestanswer');

Your code has two problems:

1. The selector .IsBestAnswe does not match what you thought
2. It's addClass(), not addclass().

Also, I'm not sure whether you want to replace the class or add it. The above will replace, but remove the .removeClass('IsBestAnswer') part to add only:

$('.IsBestAnswer').addClass('bestanswer');

You should decide whether to use camelCase or all-lowercase in your CSS classes too (e.g. bestAnswer vs. bestanswer).