JavaScript: iterating over document.evaluate() XPathResult returns null

问题

I am trying to get all objects but it doesn't work.

var tmp = document.evaluate("//tr", document, null, XPathResult.ANY_TYPE, null);

tmp.iterateNext returns me null;

回答1:

If you are working in IE, then you should know that document.evaluate does not exist there (see this similar question and the last couple of paragraphs here).

Why not just document.getElementsByTagName("tr");?

回答2:

In my opinion, using an existing JS libraries such as JQuery is usually more reliable in cases like this.

回答3:

document.getElementsByTagName("tr"); 

It also will not work, because IE some versions doesn't support this method for elements, which has not such attribute like 'name'.

来源：https://stackoverflow.com/questions/1934019/javascript-iterating-over-document-evaluate-xpathresult-returns-null