JavaScript Injection

Run JavaScript on the website before taking a screen capture, such as modifying elements on the page.

Use base64 encoded JavaScript in querystring parameters.
It is recommended to use base64 encoding for the JavaScript when it is injected via the URL using the script query string parameter. If the total URL lenght is beyong 2,000 characters, use a POST request instead.

JavaScript Injection Example

Here is the original page that we'd like to change.

Original Screenshot before JavaScript Injection

Let's say we'd like to run custom JavaScript on a page to:
1) change the background of the page to gray and to
2) disable the "I'm Feeling Lucky" button.

The JavaScript to run on the page is shown below.

// Change the background to gray document.body.style.background = "gray";
// Disable the second button on the page with the name btnI document.getElementsByName("btnI")[1].style.display = "none";

The next step is to base64 encode the JavaScript so that we can include the script in the URL query string as shown below.

ZG9jdW1lbnQuYm9keS5zdHlsZS5iYWNrZ3JvdW5kID0gImdyYXkiOwpkb2N1bWVudC5nZXRFbGVtZW50c0J5TmFtZSgiYnRuSSIpWzFdLnN0eWxlLmRpc3BsYXkgPSAibm9uZSI7

The complete request to take a screenshot and to run JavaScript on the page before taking a screenshot is shown below:

// Line breaks added for readability https://api.addscreenshots.com/screenshots
?apikey=YOUR_API_KEY
&script=ZG9jdW1lbnQuYm9keS5zdHlsZS5iYWNrZ3JvdW5kID0gImdyYXkiOwpkb2N1bWVudC5nZXRFbGVtZW50c0J5TmFtZSgiYnRuSSIpWzFdLnN0eWxlLmRpc3BsYXkgPSAibm9uZSI7
&url=google.com

The final result is shown below with only 1 button and a gray background.