Question

I would like to write a jQuery ‘plugin’ that essentially accepts a CSS class and denies it from ever being added to a given selector. Is this even possible? I cannot figure out how to actually intercept the addClass method and check it without going into the jQuery source code – and my experience with javascript is not nearly strong enough to be comfortable trying that. Plus I am loading jQuery through a CDN, so I’d rather not muck around in its source.

Answer 1

You could overwrite it like this if you accept hardcoding denied classes. You can add this anywhere, it will simply ‘patch’ jQuery with an enhanced addClass function.

http://jsfiddle.net/pimvdb/A8ePY/1/

(function($) {

// keep copy of original function
var old = $.fn.addClass;

$.fn.addClass = function(classes) {
    var spl = classes.split(" ");

    // remove denied class if present
    if(spl.indexOf("denied") > -1) {
        spl.splice(spl.indexOf("denied"), 1);
    }

    // pass everything to original function (altered classes plus other arguments)
    return old.apply(this,
                     spl.concat([].slice.call(arguments, 1)));
};

})(jQuery);