I'm trying to implement an application to interact with a website(similar to selenium) using the v8 engine. If I load a string that represents the HTML into the v8 javascript, what's the best way to interact with it. From what I've looked at, there seem to be two possible solutions: (1) Implement the DOM manually using C++ and bind it to v8 or (2) Find an existing DOM model and use that.
Which one of these solutions would be easier, or is there another better solution?
Using an existing implementation is a lot easier than writing your own. The DOM is huge.
In fact, I'd go as far as saying: to interact with a website, you don't want just a JavaScript engine (like V8) with a few additions. You most probably want a full web renderer. I don't have any specific suggestions (1) because I don't know that space very well and (2) because you haven't described what exactly you want to do. It could be that Selenium or Puppeteer are your best options; or maybe the Chromium Embedded Framework; or maybe the Qt WebEngine; etc.
V8 is just a JavaScript engine [1]. It doesn't know anything about HTML, or the DOM, or CSS, etc. var html = "<button onclick=...>click me</button>"; is just a meaningless string to V8. It doesn't know what a button is, or an onclick handler. You can't use it to draw a button onto the screen. If you tried e.g. eval(html), you'd get a SyntaxError, because that string isn't valid JavaScript, and V8 only deals with JavaScript.
[1] or more accurately: an ECMAScript engine. Defining colloquial terms is a bit tricky; some people say that "JavaScript" and "ECMAScript" are synonyms, others say that "JavaScript" == "ECMAScript language core + DOM bindings and other common browser stuff".
