Testing accessibility using Mac VoiceOver for web pages

I am working on developing/testing accessibility of a web page using VoiceOver [Mac Tool].

Typical workflow I am using is trial and error,

1. Do changes to HTML
2. Open page in browser
3. Turn on VoiceOver and test and again #1

What I understand is VoiceOver convert/see HTML/Webpage in text form and starts reading it. I hope how it does it would make it easy for me to understand how to make process easy.

So I want to know if there is any tool or utility or guidelines which could assist me to see HTML/Webpage the way VoiceOver does. I mean tool which take html as input and then output text file like VoiceOver (JUST to understand what changes affects VoiceOver in what way quickly).

Any inputs will be really helpful.