$.fn.imageLazyload = function(options) {
    var lazyloadApis = [];
    this.each(function() {
      var self = this;
      var lazyloadApi = null;
      if (self === document || self === window) {
        self = document.body;
      }
 //对，bug就在这，判定时如果body已有该属性，就不在加载了，整体的代码没看明白，注释太少了啊
      var id = self.getAttribute('data-imageLazyload');
      if (!id) {
        id = ++$.uuid;
        $.data[id] = lazyloadApi = new ImageLazyload(self, options);
        self.setAttribute('data-imageLazyload', id);
      } else {
        lazyloadApi = $.data[id];
      }
      lazyloadApis.push(lazyloadApi);
    });
    return lazyloadApis.length === 1 ? lazyloadApis[0] : lazyloadApis;
  }

document.body.removeAttribute('data-imagelazyload');
  mui(document).imageLazyload({
    placeholder: '../../images/img_head3.png'
  });