var klass = {

    exists: function(el, name) {
        var list = el.className.split(' ');
        for (var i = 0; i < list.length; i++) if (list[i] == name) return true;
        return false;
    },
    append: function(el, name) {
        if (el.className == name) return;
        if (el.className.indexOf(name + ' ') > -1) return;
        if (el.className.indexOf(' ' + name) > -1) return;
        if (el.className) name = ' ' + name;
        el.className += name;
    },
    remove: function(el, name) {
        if (el.className == '') return;
        if (el.className == name) return el.className = '';
        el.className = el.className.replace(' ' + name, '');
        el.className = el.className.replace(name + ' ', '');
    }
}