How to get the number of site pages in Yandex from popup.html?

Question

Google Chrome

At the moment, the difficulty in general is that I can’t access the finished DOM of the page, for example https://yandex.ru/search/?lr=213&text=test
If I do this in popup.js

$.get("https://yandex.ru/search/?lr=213&text=тест", function(html){
  var a = $(html).text();
  alert(a)
});

Then the variable a will contain the html response, but not the finished DOM with the executed js. How to get ready DOM?