javascript实现替换图片的问题

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 这段代码怎么不能实现替换图片呢

解决方案 »

  1.   

    var img = document.getElementsByTagName("img");
    这句错误：应该改成var img = document.getElementsByTagName("img")[0];
    getElementsByTagName("img")它会得到所有的img节点，放在一个类似于数组的东西中，后面加[0]就明确了要得到那一个img节点。另外你点一下连接i就加了一次，小心数组越界啊！！还有script代码最好不要放在body中啊，因为这样加载文档时就执行了，正常是放在head中的，可以用onload事件控制脚本在dom文档加载完再执行！不过也有高人建议放在文档的最后，这样也可以在加载完之后执行，不过很少有人这么做！
      

  2.   

    2楼正解，另外a标签里的return false有什么作用呢
      

  3.   

    嗯 关于越界这个我知道   关键是我的功能没实现 我还没心情去理会越界 还有getElementsByTagName这个谢谢各位的提醒 本来是写ById的 后来复制别人的代码忘记改
      

  4.   

    var img = document.getElementsByTagName("img")[0];你的定义是var img = document.getElementsByTagName("img")；
    这样子，img就是一个数组！！！不是一个具体的元素。
      

  5.   

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    var i = 0;
    function next() {
       i < len &&  (img[i++].src = urlArray[i]);
    }
      

  6.   

    没看清楚要求.开始写错了.换成var i = 0;
    function next() { 
      i < len &&  (img[0].src = urlArray[i++]);
    }