如何访问没有ID的HTML元素？ [英] How to access HTML element without ID?

问题描述

例如下面的代码段 - 如何访问知道父元素（header-inner div）的ID的h1元素？

For instance in the snippet below - how do I access the h1 element knowing the ID of parent element (header-inner div)?

<div id='header-inner'> 
   <div class='titlewrapper'> 
      <h1 class='title'> 
      Some text I want to change
      </h1> 
   </div> 
</div>

谢谢！

推荐答案

function findFirstDescendant(parent, tagname)
{
   parent = document.getElementById(parent);
   var descendants = parent.getElementsByTagName(tagname);
   if ( descendants.length )
      return descendants[0];
   return null;
}

var header = findFirstDescendant("header-inner", "h1");

找到具有给定ID的元素，查询具有给定标签名称的后代，返回第一个。您也可以循环后代以过滤其他条件;如果你开始朝这个方向前进，我建议你检查一个预建的库，如jQuery（会节省你很多时间写这个东西，它有点棘手）。

Finds the element with the given ID, queries for descendants with a given tag name, returns the first one. You could also loop on descendants to filter by other criteria; if you start heading in that direction, i recommend you check out a pre-built library such as jQuery (will save you a good deal of time writing this stuff, it gets somewhat tricky).

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