HTML 集合结构在所有浏览器中都相同

HTML collection structure same in all browsers

当您使用 document.getElementsByTagName() 搜索元素时,我们得到 HTMLCollection。如果元素具有 id,则输出具有 indexid 的元素。

问题是,这个结构会在所有浏览器中保持不变还是会改变?

例子

(function() {
  var inputs = document.getElementsByTagName("div")[0].children;
  console.log(inputs);
})()
<div id="content">
  <input type="text" id="input1" />
  <input type="text" id="input2" />
  <input type="text" id="input3" />
  <input type="text" id="input4" />
</div>

如果有多个元素匹配用作索引的字符串,您不能指望浏览器这样做。

Browser compatibility
Different browsers behave differently when there are more than one elements matching the string used as an index (or namedItem's argument). Firefox 8 behaves as specified in DOM 2 and DOM4, returning the first matching element. WebKit browsers and Internet Explorer in this case return another HTMLCollection and Opera returns a NodeList of all matching elements.

来源:https://developer.mozilla.org/en-US/docs/Web/API/HTMLCollection