如何使用 javascript 获取当前焦点（活动）网页的 DOM 树

Question

I am trying to make a java software in which I am giving an option to switch to 'Browser' mode. As soon as the user selects it and visits any web page, the user can select any word from the current webpage and see its definition. The user should be able to switch between web pages and still leverage the functionality(and hence the current active web page's DOM tree). Thought of creating a Mozilla or Chrome extension first, but this has to be the part of Java software and browsers these days don't allow installing extension via a software. I have tried: window.document.getElementsByTagName('p')[0].innerHTML to get all the <p> content of the current page but it doesn't work.

Answer 1

To return all the <p> contents you can do:

var items = [...window.document.getElementsByTagName('p')];
var result = items.map(obj => obj.innerHTML);

It will return an array of contents