Question

我在我的网站上使用此代码在我向下滚动页面时加载图片：http://css-tricks.com/snippets/javascript/lazy-loading-images/

您可以在此处查看我在哪里使用它：http://www.easythemepro.com/themes.php

我已将此Javascript代码添加到我的标题中：

<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
<script type="text/javascript">
!function(window){
  var $q = function(q, res){
        if (document.querySelectorAll) {
          res = document.querySelectorAll(q);
        } else {
          var d=document
            , a=d.styleSheets[0] || d.createStyleSheet();
          a.addRule(q,'f:b');
          for(var l=d.all,b=0,c=[],f=l.length;b<f;b++)
            l[b].currentStyle.f && c.push(l[b]);

          a.removeRule(0);
          res = c;
        }
        return res;
      }
    , addEventListener = function(evt, fn){
        window.addEventListener
          ? this.addEventListener(evt, fn, false)
          : (window.attachEvent)
            ? this.attachEvent('on' + evt, fn)
            : this['on' + evt] = fn;
      }
    , _has = function(obj, key) {
        return Object.prototype.hasOwnProperty.call(obj, key);
      }
    ;

  function loadImage (el, fn) {
    var img = new Image()
      , src = el.getAttribute('data-src');
    img.onload = function() {
      if (!! el.parent)
        el.parent.replaceChild(img, el)
      else
        el.src = src;

      fn? fn() : null;
    }
    img.src = src;
  }

  function elementInViewport(el) {
    var rect = el.getBoundingClientRect()

    return (
       rect.top    >= 0
    && rect.left   >= 0
    && rect.top <= (window.innerHeight || document.documentElement.clientHeight)
    )
  }

    var images = new Array()
      , query = $q('img.lazy')
      , processScroll = function(){
          for (var i = 0; i < images.length; i++) {
            if (elementInViewport(images[i])) {
              loadImage(images[i], function () {
                images.splice(i, i);
              });
            }
          };
        }
      ;
    // Array.prototype.slice.call is not callable under our lovely IE8 
    for (var i = 0; i < query.length; i++) {
      images.push(query[i]);
    };

    processScroll();
    addEventListener('scroll',processScroll);

}(this);?
</script>

我正在使用此格式显示图片：

<img src="img/blank.png" data-src="demo/wp-content/themes/Alfina/screenshot.png" width="300" height="225" class="lazy">

您可以在http://css-tricks.com/examples/LazyLoading/的演示页面上查看此代码的工作位置，但我无法弄清楚是什么导致它无法在我的页面上运行...

任何帮助将不胜感激！

Answer 1

用此脚本替换您的功能

$(function() {
  var $q = function(q, res){
        if (document.querySelectorAll) {
          res = document.querySelectorAll(q);
        } else {
          var d=document
            , a=d.styleSheets[0] || d.createStyleSheet();
          a.addRule(q,'f:b');
          for(var l=d.all,b=0,c=[],f=l.length;b<f;b++)
            l[b].currentStyle.f && c.push(l[b]);

          a.removeRule(0);
          res = c;
        }
        return res;
      }
    , addEventListener = function(evt, fn){
        window.addEventListener
          ? this.addEventListener(evt, fn, false)
          : (window.attachEvent)
            ? this.attachEvent('on' + evt, fn)
            : this['on' + evt] = fn;
      }
    , _has = function(obj, key) {
        return Object.prototype.hasOwnProperty.call(obj, key);
      }
    ;

  function loadImage (el, fn) {
    var img = new Image()
      , src = el.getAttribute('data-src');
    img.onload = function() {
      if (!! el.parent)
        el.parent.replaceChild(img, el)
      else
        el.src = src;

      fn? fn() : null;
    }
    img.src = src;
  }

  function elementInViewport(el) {
    var rect = el.getBoundingClientRect()

    return (
       rect.top    >= 0
    && rect.left   >= 0
    && rect.top <= (window.innerHeight || document.documentElement.clientHeight)
    )
  }

    var images = new Array()
      , query = $q('img.lazy')
      , processScroll = function(){
          for (var i = 0; i < images.length; i++) {
            if (elementInViewport(images[i])) {
              loadImage(images[i], function () {
                images.splice(i, i);
              });
            }
          };
        }
      ;
    // Array.prototype.slice.call is not callable under our lovely IE8 
    for (var i = 0; i < query.length; i++) {
      images.push(query[i]);
    };

    processScroll();
    addEventListener('scroll',processScroll);

  });

Fiddle DEMO

向下滚动页面加载图像不起作用？

1 个答案: