jquery addClass() to first position of multiple classes

 (function($) {

    jQuery.fn.extend({
        prependClass: function(newClasses) {
            return this.each(function() {
                var currentClasses = $(this).prop("class");
                $(this).removeClass(currentClasses).addClass(newClasses + " " + currentClasses);
            });
        }
    });

})(jQuery);

function prependClass(sel, strClass) {
    var $el = jQuery(sel);

    /* prepend class */
    var classes = $el.attr('class');
    classes = strClass +' ' +classes;
    $el.attr('class', classes);
}