How to remove all instances of a class in javascript/jquery?

I have this class called .m-active that is used multiple times throughout my HTML.

Basically what I want to do is remove all instances of that class when a user clicks on an image (which does not have the m-active class) and add the m-active class to that image.

For instance in a Backgrid row you might have a click handler as follows:

"click": function () {
    this.$el.addClass('m-active');
}

But you also want to remove that class from any rows to which it was previously added, so that only one row at a time has the .m-active class

Does anyone know how this can be done in javascript/jquery?

With jQuery:

$('.m-active').removeClass('m-active');

Explanation:

• Calling $('.m-active') selects all elements from the document that contain class m-active
• Whatever you chain after this selector gets applied to all selected elements
• Chaining the call with removeClass('m-active') removes class m-active from all of the selected elements

For documentation on this specific method, see: http://api.jquery.com/removeClass/

Getting grasp of the whole selector thing with jQuery is challenging at first, but once you get it, you see everything in very different light. I encourage you to take a look into some good jQuery tutorials. I personally recommend checking out Codeacademy's jQuery track: http://www.codecademy.com/tracks/jquery