Using JQuery removeClass() to remove all classes but one

Question

Okay, I've got an interesting one (well, interesting to me, anyway :) ).

I've got a situation where I have a div with a static class value, but it also can have a single, "secondary class" assigned that is dynamic. When the user makes a selection, any existing secondary class needs to be removed and the new class added.

Ignoring using an id value (standards for the project use the class . . . can't be changed), is there an elegant way to simply ignore the first class and remove whatever other class is there, before adding the new one?

Example Starting HTML:

<div class="staticClass dynaClass1" />

Example JS:

function updateClass(newSecondaryClass) {
    $(".staticClass") . . . **** remove any class besides "staticClass" ****
    $(".staticClass").addClass(newSecondaryClass);
}

If the function is called using updateClass("dynaClass2");, the resulting HTML should be:

<div class="staticClass dynaClass2" />

I can think of ways of doing it involving just removing all classes using removeClass(); and adding "staticClass" back in when adding the new class, or using attr("class", "staticClass " + newSecondaryClass);, but I'm wondering if there isn't a way to handle it without having to touch the static class at all?

In the end, I guess this is an academic question, more than anything . . . just seems like it's something that should be doable, but I don't know how to do it. :D

Answer 1

You can remove all classes and add the one you want to leave:

$(".staticClass").removeClass().addClass('staticClass');

Calling removeClass() without a parameter removes all classes.

If you don't want to do that then you can simply modify the class attribute:

$(".staticClass").attr('class', 'staticClass');

Answer 2

You can pass a function to remove class, which returns all but the static Classes:

$('.staticClass').removeClass(function(index, klass) { 
  return klass.replace(/(^|\s)+staticClass\s+/, ''); 
})

This is returning all the classes that are on the object, without the static one, and therefore removes all classes but the static one.