Question

HTML如何获取comment（注释）元素对象？

获取普通的元素可以用document.getElementById(id)，但是注释元素既没有名字也没有ID该怎么获取呢？

Answer 1

参考：
// ie9以前
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;
}

ie9以后：
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));
});