Get meta data attribute in javascript

Question

I am having trouble retrieving information from a meta tag. I am trying to get an img src from a website and can't quite figure it out. Here is an example of what I am trying to do.

<meta property="og:image" content="http://foo.jpg">
var image = document.querySelector('meta[property="og:image"]').getAttribute('content');

I have tried this but it doesn't work. Any ideas?

Answer 1

meta elements aren't special, you can query for them and get their attributes in the normal way.

In this case, here's how you'd get the content attribute value from the first meta[property="og:image"] element:

var element = document.querySelector('meta[property~="og:image"]');
var content = element && element.getAttribute("content");

querySelector is supported by all modern browsers, and also IE8.

Note that the content property is also available as a reflected property, so you can just use .content rather than .getAttribute("content"):

var element = document.querySelector('meta[property~="og:image"]');
var content = element && element.content;

In modern JavaScript you can use the optional chaining operator (?.) to combine those two statements:

const content = document.querySelector('meta[property~="og:image"]')?.content;
// −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−^

If the element isn't found, content will get the value undefined; otherwise, it'll get the value of the reflected property (which is the attribute value).