text: /**
   * Created by qhyang on 2017/3/24.
   */
  
  $.fn.stairwayNav = function(options) {
  
      var defaults = {
          stairs: 3
      };
      this.options = $.extend({}, defaults, options);
      var stairs = this.options.stairs;
  
      var allLinks = this.find("a");
  
      allLinks
          .mouseenter(function() {
              $(this).addClass("active-1");
              var index = $(this).index(), i, bef, aft;
              for(i = 1; i < stairs; i++) {
  
                  bef = index - i;
                  aft = index + i;
  
                  allLinks.eq(aft).addClass("active-" + (i+1));
                  if (bef > 0) {
                      allLinks.eq(bef).addClass("active-" + (i+1));
                  }
              }
          })
          .mouseleave(function() {
              allLinks.removeClass("active-1 active-2 active-3 active-4");
          });
      return this;
  };
  