js:类名exist/增加/替换实现

CHRD.clas = {
    exist : function(el, name) {//是否有
        return (' ' + el.className + ' ').indexOf(' ' + name + ' ') > -1;
    }
}
CHRD.clas.add = function (el, name){//
    ! CHRD.clas.exist(el, name) && (el.className = el.className + ' ' + name);
}
CHRD.clas.re=function (el, name, newName){//替换
    el.className = CHRD.trim((' ' + el.className + ' ').replace(' ' + name + ' ', '')) + ' ' + (newName ? newName : '');
}