Logo Questions Linux Laravel Mysql Ubuntu Git Menu
 

How can I check that an element is visible with Puppeteer and pure JavaScript?

Tags:

I wish to check that a DOM element is visible with Puppeteer and pure JavaScript (not jQuery), how can I do this? By visible I mean that the element is displayed through CSS, and not hidden (f.ex. by display: none).

For example, I can determine whether my element #menu is not hidden via CSS rule display: none, in the following way:

const isNotHidden = await page.$eval('#menu', (elem) => {
  return elem.style.display !== 'none'
})

How can I determine in general though if the element is hidden or not, and not just through display: none?

like image 979
aknuds1 Avatar asked Dec 08 '17 10:12

aknuds1


People also ask

How do you know if a element is visible or not in puppeteer?

If we are not interested in waiting on the element, and we would simply like to test the visibility of the element, we can use a combination of getComputedStyle() and getBoundingClientRect() to test whether or not the element is visible.

How do you check if an element is visible on the web page Javascript?

Summary. Use the getBoundingClientRect() method to get the size of the element and its relative position to the viewport. Compare the position of the element with the viewport height and width to check if the element is visible in the viewport or not.


2 Answers

I found that Puppeteer has an API method for this purpose: Page.waitForSelector, via its visible option. I wasn't aware of the latter option, but it lets you wait until an element is visible.

await page.waitForSelector('#element', {
  visible: true,
})

Conversely you can wait for an element to be hidden, via the hidden option.

I think this is the idiomatic answer, with regards to the Puppeteer API. Thanks to Colin Cline though as I think his answer is probably useful as a general JavaScript solution.

like image 52
aknuds1 Avatar answered Sep 21 '22 22:09

aknuds1


One is by checking its display style value. Second is by checking its height, for exp if the element is a child of an element which is display: none, the offsetHeight will be 0 and thus you know the element is not visible despite its display value. opacity: 0 is not considered as hidden element so we will not checking it.

const isNotHidden = await page.$eval('#menu', (elem) => {
    return window.getComputedStyle(elem).getPropertyValue('display') !== 'none' && elem.offsetHeight
});

You can check elem.offsetWidth as well and is not bad before any calculation, check if element exist or not.

like image 34
Colin Cline Avatar answered Sep 22 '22 22:09

Colin Cline