zepto 扩展prevAll(),nextAll()方法

$.fn.prevAll = function(selector){

 var prevEls = [];

 var el = this[0];

 if(!el) return $([]);

 while (el.previousElementSibling) {

        var prev = el.previousElementSibling;

        if (selector) {

          if($(prev).is(selector)) prevEls.push(prev);

        }

        else prevEls.push(prev);

        el = prev;

      }

      return $(prevEls);

};

 

$.fn.nextAll = function (selector) {

      var nextEls = [];

      var el = this[0];

      if (!el) return $([]);

      while (el.nextElementSibling) {

        var next = el.nextElementSibling;

        if (selector) {

          if($(next).is(selector)) nextEls.push(next);

        }

        else nextEls.push(next);

        el = next;

      }

      return $(nextEls);

    };