i am trying to develop an extension for firefox it will check my server status from my website and set it in extension so i want to save time to not checking it hour by hour.

document.evaluate('XPATH HERE', document, null, XPathResult.FIRST_ORDERED_NODE_TYPE, null).singleNodeValue;

here is my code block

how should i set command to have exact url example-"google.com" 's data?

I have tried to google it but i couldn't find any informacion so far.