1 var FastRender = new inherit({
 2 
 3   initialize: function(opts) {
 4     this.handleOpts(opts);
 5     this.init();
 6   },
 7 
 8   handleOpts: function(opts) {
 9     if (!opts || !opts.doms || !opts.doms.length) throw ‘FastRender param error‘;
10     this.doms = opts.doms;
11     this.container = opts.container || $(window);
12     this.renderContainer = {};
13     this.step = 50;
14 
15   },
16 
17   init: function() {
18     this.initImgContainer();
19     this.initRender();
20     this.bindEvents();
21   },
22 
23   bindEvents: function() {
24 
25     //为container绑定事件
26     this.container.on(‘scroll.fastRender‘, $.proxy(function() {
27       this.initRender();
28     },
29     this));
30   },
31 
32   initImgContainer: function() {
33     var el, i, len, offset;
34     for (i = 0, len = this.doms.length; i < len; i++) {
35       el = $(this.doms[i]);
36       offset = el.offset();
37 
38       //这块卡
39       //      (function (el) {
40       //        setTimeout(function () {
41       el.css({
42         ‘width‘: offset.width,
43         ‘height‘: offset.height
44       });
45       //        }, 0);
46       //      })(el);
47 
48       if (!this.renderContainer[offset.top]) {
49         this.renderContainer[offset.top] = [];
50       }
51       this.renderContainer[offset.top].push(el);
52     }
53 
54   },
55 
56   /*
57         这里需要对对象遍历做优化，以坐标搜索替换数值搜索
58 
59         */
60   initRender: function() {
61     var height = this.container.height();
62     var srollHeight = this.container.scrollTop();
63     var k, _imgs, el, i, len, els;
64 
65     this.doms.removeClass(‘wl‘);
66 
67     for (k in this.renderContainer) {
68       //                        if ((parseInt(k) < srollHeight + height + this.step) && (parseInt(k) > srollHeight - this.step)) {
69       if ((parseInt(k) < srollHeight + height - this.step) && (parseInt(k) > srollHeight + this.step)) {
70 
71         els = this.renderContainer[k];
72         for (i = 0, len = els.length; i < len; i++) {
73           el = $(els[i]);
74           el.find(‘.lazy_wrapper‘).show();
75         }
76       } else {
77         els = this.renderContainer[k];
78         for (i = 0, len = els.length; i < len; i++) {
79           el = $(els[i]);
80           el.find(‘.lazy_wrapper‘).hide();
81         }
82 
83       }
84     } // for
85 
86   },
87 
88   destroy: function() {
89     //为container绑定事件
90     this.container.off(‘.fastRender‘);
91   }
92 
93 });
94 
95 var f = new FastRender({
96   doms: $(‘.js_hotel_detail‘)
97 });