lib/tethys.js
function(key, value){

        return keyValue.call(this, arguments, function(el){
            return el.getAttribute(key);
        }, function(el, key, attrs){
            el.setAttribute(key, attrs[key] + '');
        });
    }
function(key, value){

        return keyValue.call(this, arguments, function(el){
            return el.getAttribute(key);
        }, function(el, key, attrs){
            el.setAttribute(key, attrs[key] + '');
        });
    }
设置或者返回属性