javascript - 从 DOM 解析 HTML

Question

我正在尝试从以下 HTML 代码中解析替代文本，这些代码是我从 Xpath 中获得的，表示为“FIRST_RECORD_LINK”。

<img data-aria-label-part="" src="https://pbs.twimg.com/media/Dc10VX_UwAAJxPM.jpg" alt="Millenials are more likely than Baby Boomers to be living with a disability. 
Provided by the Center for Talent Innovation Disability Inclusion Report."> 

我的 javascript 代码如下所示:

var FIRST_RECORD_LINK = '//*[@id="stream-item-tweet-999772032685527042"]/div[1]/div[2]/div[3]/div/div/div/div/img';
var FIRST_RECORD = document.evaluate(FIRST_RECORD_LINK, document, 
    null, XPathResult.ANY_TYPE, null).iterateNext();
console.log(FIRST_RECORD); 
var parser = new DOMParser();
var xmlDoc = parser.parseFromString(FIRST_RECORD,"text/html");
console.log(xmlDoc.getElementsByTagName("img")[0].childNodes[0].getAttribute("alt"));

我做错了什么？对于没有使用代码框，我提前表示歉意，我有视力障碍，而且它们不支持我的屏幕阅读器。

Answer 1

通过评估 xpath 获得 FIRST_RECORD 中的 img 后，您可以使用 getAttribute 读取 alt 属性:

FIRST_RECORD.getAttribute('alt');

查看一个工作示例(使用更新的 xpath，以便它在 stackoverflow 中工作):

// The following path was modified to work in stackoverflow
var FIRST_RECORD_LINK = '//img';
var FIRST_RECORD = document.evaluate(FIRST_RECORD_LINK, document, null, XPathResult.ANY_TYPE, null).iterateNext();
console.log(FIRST_RECORD);
console.log(FIRST_RECORD.getAttribute('alt'));

<img data-aria-label-part="" src="https://pbs.twimg.com/media/Dc10VX_UwAAJxPM.jpg" alt="Millenials are more likely than Baby Boomers to be living with a disability. 
Provided by the Center for Talent Innovation Disability Inclusion Report.">