If doing a lot of 2way comm, requests is easiest to use. You can then display the result in a webview.
For simple stuff, eval_js works well. You can use
eval_js('document.documentElement.innerHTML')to get current page source. Then you can use bs4 for example to scrape the source.
See http://www.w3schools.com/jsref/met_html_click.asp for an example of directly simulating a mouse click on an element like a button.