How locate the pseudo-element ::before using Selenium Python

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Question :

How locate the pseudo-element ::before using Selenium Python

I’m using Selenium Python to locate label element.I want to use ::before to locate it,because this is a pop window.

 <div class="crow" grp="0" grpname="Pizza Size">
    ::before
    <label class="label0" cid="1">
    <input type="radio" name="0" coname="M" sname="" price="9.99" value="392">M<b class="ip">9.99</b>
    </label>
    <label class="label0" cid="1"><input type="radio" name="0" coname="L" sname="" price="11.99" value="393">L<b class="ip">11.99</b>
    </label><div style="clear:both">
    </div>
    </div>

I have no idea how to use ::before to locate it,any friend can help?

Asked By: William

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Answer #1:

Pseudo Elements

A CSS pseudo-element is used to style specified parts of an element. It can be used to:

  • Style the first letter, or line, of an element
  • Insert content before, or after, the content of an element

::after

::after is a pseudo element which allows you to insert content onto a page from CSS (without it needing to be in the HTML). While the end result is not actually in the DOM, it appears on the page as if it is, and would essentially be like this:

CSS:

div::after {
  content: "hi";
}

::before

::before is exactly the same only it inserts the content before any other content in the HTML instead of after. The only reasons to use one over the other are:

  • You want the generated content to come before the element content, positionally.
  • The ::after content is also “after” in source-order, so it will position on top of ::before if stacked on top of each other naturally.

Demonstration of extracting properties of

As per the discussion above you can’t locate the ::before element within the DOM Tree but you can always be able to retrieve the contents of the pseudo-elements, i.e. ::before and ::after elements. Here’s an example:

To demonstrate, we will be extracting the content of ::after element (snapshot below) within this website:

after_element

  • Code Block:

    from selenium import webdriver
    
    options = webdriver.ChromeOptions() 
    options.add_argument("start-maximized")
    options.add_experimental_option("excludeSwitches", ["enable-automation"])
    options.add_experimental_option('useAutomationExtension', False)
    driver = webdriver.Chrome(options=options, executable_path=r'C:WebDriverschromedriver.exe')
    driver.get('https://meyerweb.com/eric/css/tests/pseudos-inspector-test.html')
    script = "return window.getComputedStyle(document.querySelector('body>p.el'),':after').getPropertyValue('content')"
    print(driver.execute_script(script).strip())
    
  • Console Output:

    " (fin.)"
    

This console output exactly matches the value of the content property of the ::after element as seen in the HTML DOM:

after_content


This usecase

To extract the value of the content property of the ::before element you can use the following solution:

script = "return window.getComputedStyle(document.querySelector('div.crow'),':before').getPropertyValue('content')"
print(driver.execute_script(script).strip())

Outro

A couple of relevant documentations:

Answered By: DebanjanB

Answer #2:

If I am not wrong, then, selenium doesn’t provide any function or API call for this.
You can try parsing the html and then finding the tag using a simple regular expression.
Hope this helps 🙂

Answered By: Debdut Goswami

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