如何使用javascript获得HTML评论 [英] How do I get an HTML comment with javascript

问题描述

如果我有

 <！ - 一些评论 - > 
  

如何获取此元素并使用javascript更改内容？
如果我有一个代码在里面，我想删除评论的标签，我该怎么做？

解决方案

< h2>使用NodeIterator（IE> = 9）

最好的方法是使用专门的 NodeIterator 实例迭代给定根元素中包含的所有注释。

$ b

看到它在行动！

  function filterNone（）{
返回NodeFilter.FILTER_ACCEPT; 
} 
 
函数getAllComments（rootElem）{
 var comments = []; 
 //第四个参数，根据DOM4标准，它实际上已经过时，在IE 11 
中需要var iterator = document.createNodeIterator（rootElem，NodeFilter.SHOW_COMMENT，filterNone，false）; 
 var curNode; 
 while（curNode = iterator.nextNode（））{
 comments.push（curNode.nodeValue）; 
} 
返回评论; 
 
 $ b $ window.addEventListener（load，function（）{
 console.log（getAllComments（document.body））; 
}）; 
  

使用自定义的DOM遍历（也支持IE< 9）

如果您必须支持旧浏览器（例如IE< 9），则需要自己遍历DOM并提取那些节点类型是 Node.COMMENT_NODE 。

看到它在行动！

  //感谢Yoshi的提示！ 
 // Polyfill for IE< 9 
 if（！Node）{
 var Node = {}; 
 
 if（！Node.COMMENT_NODE）{
 //根据DOM规范的数值
 Node.COMMENT_NODE = 8; 
} 
 
函数getComments（elem）{
 var children = elem.childNodes; 
 var comments = []; 
 
 for（var i = 0，len = children.length; i< len; i ++）{
 if（children [i] .nodeType == Node.COMMENT_NODE）{
 comments.push（children [i]）; 
} 
} 
返回评论; 
} 
  

提取节点的内容并将其删除

独立于您从上面选择的方式，您会收到相同节点的DOM对象。

访问注释内容非常简单，只需 commentObject.nodeValue 。

删除评论有点冗长： commentObject.parentNode.removeChild（commentObject）

If I have that

  <!-- some comment -->

How do I get this element and change the content with javascript? And if I have a code inside that and I want to delete the tag of comments how can I do it?

解决方案

Using a NodeIterator (IE >= 9)

The best method is to use a dedicated NodeIterator instance iterating all comments contained in a given root element.

See it in action!

function filterNone() {
    return NodeFilter.FILTER_ACCEPT;
}

function getAllComments(rootElem) {
    var comments = [];
    // Fourth argument, which is actually obsolete according to the DOM4 standard, is required in IE 11
    var iterator = document.createNodeIterator(rootElem, NodeFilter.SHOW_COMMENT, filterNone, false);
    var curNode;
    while (curNode = iterator.nextNode()) {
        comments.push(curNode.nodeValue);
    }
    return comments;
}

window.addEventListener("load", function() {
    console.log(getAllComments(document.body));
});

Using a custom-made DOM traversal (to support IE < 9 as well)

If you have to support older browsers (e.g. IE <9), you need to traverse the DOM yourself and extract those elements whose node type is Node.COMMENT_NODE.

See it in action!

// Thanks to Yoshi for the hint!
// Polyfill for IE < 9
if (!Node) {
    var Node = {};
}
if (!Node.COMMENT_NODE) {
    // numeric value according to the DOM spec
    Node.COMMENT_NODE = 8;
}

function getComments(elem) {
  var children = elem.childNodes;
  var comments = [];

  for (var i=0, len=children.length; i<len; i++) {
    if (children[i].nodeType == Node.COMMENT_NODE) {
      comments.push(children[i]);
    }
  }
  return comments;
}

Extracting a node's contents and delete it

Independent of the way you choose from above, you receive the same node DOM objects.

Accessing a comment's contents is as easy as commentObject.nodeValue.
Deleting a comment is a bit more verbose: commentObject.parentNode.removeChild(commentObject)

这篇关于如何使用javascript获得HTML评论的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！