Modifying this control will update this page automatically

Use the Run JavaScript on Web Page action in Shortcuts on iPhone or iPad
Use the Run JavaScript on Web Page action to retrieve specific data from a website, or to modify the contents of a web page.

The Run JavaScript on Web Page action contains a text field where you write your own script. You run the shortcut from the Safari app. Before you can run JavaScript from a shortcut, you must turn on Allow Running Scripts. See Advanced Privacy and security settings in Shortcuts on iPhone or iPad.
Note: You can also use the Run JavaScript on Web Page action in SFSafariViewController. For more information, see https://developer.apple.com/documentation/safariservices/sfsafariviewcontroller.