如何使用 AJAX 从外部网页获取未命名元素？

Question

At the moment I'm trying to get an element off an external website using AJAX, so far I've (hopefully) managed to get the page:

var xmlhttp;
var version;
if (window.XMLHttpRequest)
  {// code for IE7+, Firefox, Chrome, Opera, Safari
  xmlhttp=new XMLHttpRequest();
  }
else
  {// code for IE6, IE5
  xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
  }
xmlhttp.onreadystatechange=function()
  {
  if (xmlhttp.readyState==4 && xmlhttp.status==200)
    {
    version=xmlhttp.innerHTML;
    }
  }
xmlhttp.open("GET","http://www.minecraftwiki.net/wiki/Minecraft_Wiki",true);
xmlhttp.send();

Now I just need to find a way to get the contents:

<dd> Current PC version: 
<b>
<a href="/wiki/Version_history#1.2.5" title="Version history">
1.2.5
</a>
</b>
</dd>

I've checked the source code of the url and sadly the element I want is unnamed (Has no id=" "), so is it still possible to do so? And if so, how? Thanks

Answer 1

First, you're making a cross-domain request, so unless you're using a browser that allows cross-domain AJAX, this is most likely not going to work for you without using a server-side proxy.

However, to answer your original question, you don't need an id attribute to access an element. While helpful, you can access an element in any number of ways.

Class Selectors

var col = document.getElementsByClassName("the-class");

Then loop through the collection until you find the element you want.

jQuery Selectors:

jQuery Selectors are perhaps the easiest way to handle DOM manipulations and get access to the element you are interested in:

// example of an attribute selector:

var exampleHTML = $('div[title="example"]).html();

There is also XPath, but from my experience jQuery CSS Selectors are more modern, robust, and help speed up the development process.