递归下来的DOM树 [英] Recursion down DOM tree

问题描述

这是Crockford的JavaScript代码：Good Parts。

This is code from Crockford's JavaScript: The Good Parts.

var results = [];

var walkDOM = function (node,func) {
        func(node);                     //What does this do?
        node = node.firstChild;
        while(node) {
            walkDOM(node,func);
            node = node.nextSibling;
        }

    };

我了解代码，除了 func（node）。我想这一点是通过节点作为函数 func 中的一个参数，但浏览器如何理解？ 节点和 func 可以是任何东西 - 所以当函数被调用时，它可以这样读取：

I understand the code except for func(node). I guess the point is to pass node as a parameter in function func, but how will the browser understand it this way? node and func could be anything--so when the function is called it could read like this:

walkDOM(document.body,function(att) {
          node.getAttribute(att);
          results.push(node);
          });

当 func 被传递时， walkDOM 将处理函数（att）{...}（document.body） - 这不会有任何意义。那么为什么Crockford选择包括func（节点）？

When func is passed, walkDOM will process function(att) {...}(document.body)--which wouldn't make any sense. So why has Crockford chosen to include func(node)?

推荐答案

看起来像我这样的 func

例如，如果我想为整个树中的每个节点提醒标签名称：

For example, if I wanted to alert the tag name for every node in the entire tree:

walkDOM(document.body, function(node) {
    alert(node.tagName);
});

在您的示例函数中：

walkDOM(document.body,function(att) {
      node.getAttribute(att);
      results.push(node);
      });

...您已命名为节点参数到 att ，但这并不奇怪地在一个属性的名称中。当 node.getAttribute（att）被运行时，我会期待一个变量节点被定义，因为节点被设置为 att ...在该函数的范围内没有节点。

... you have named the node parameter to att, but that doesn't magically make in a name of an attribute. I would expect a "variable 'node' is not defined" when node.getAttribute(att) is ran, because node is being set to att... there is no node in that function's scope.

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