Change CSS class properties with jQuery

Question

Is there a way to change the properties of a CSS class, not the element properties, using jQuery?

This is a practical example:

I have a div with class

Answer 1

Here's a bit of an improvement on the excellent answer provided by Mathew Wolf. This one appends the main container as a style tag to the head element and appends each new class to that style tag. a little more concise and I find it works well.

function changeCss(className, classValue) {
    var cssMainContainer = $('#css-modifier-container');

    if (cssMainContainer.length == 0) {
        var cssMainContainer = $('');
        cssMainContainer.appendTo($('head'));
    }

    cssMainContainer.append(className + " {" + classValue + "}\n");
}