21节点之点击按钮设置div中p标签改变背景颜色

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title></title>
        <style>
            div {
          width: 300px;
          height: 450px;
          border: 1px solid red;
        }
      </style>
    </head>
    <body>
        <input type="button" value="变色" id="btn" />
        <div id="dv">
            <span>这是span</span>
            <p>这是p</p>
            <span>这是span</span>
            <p>这是p</p>
            <span>这是span</span>
            <p>这是p</p>
            <span>这是span</span>
            <a href="http://www.baidu.com">百度</a>
        </div>
        <script src="common.js"></script>
        <script type="text/javascript">
            //点击按钮 设置p标签变色===节点的方式做
            my$("btn").onclick = function() {
                //先获取div
                var dvObj = my$("dv");
                //获取dv里面的所有节点
                var nodes = dvObj.childNodes;
                for (var i = 0; i < nodes.length; i++) {
                    //判断这个节点是不是p标签
                    if (nodes[i].nodeType == 1 && nodes[i].nodeName == "P") {
                        nodes[i].style.backgroundColor="red";
                    }
                }
            };
        </script>
    </body>
</html>

效果:

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转载自www.cnblogs.com/zhangDY/p/11494609.html