// make sure the $ is pointing to JQuery and not some other library
(function($){
    // add a new method to JQuery

    $.fn.equalHeight = function(minHeight) {
       // find the tallest height in the collection
       // that was passed in (.col)
        tallest = (minHeight) ? minHeight : 0;
        this.each(function(){
            thisHeight = $(this).height();
            if( thisHeight > tallest)
                tallest = thisHeight;
        });

        // set each items height to use the tallest value found
        this.each(function(){
            $(this).height(tallest);
        });
    }
})(jQuery);