What's the best way of checking the compatibility of a website with a specific version of a browser. For instance, I know how my website will be rendered on the latest version of FireFox which I've installed it before, but I don't know how it'd be shown on previous versions.
IE has an option to render a page like previous version but firstly I've heard that it's not as the same as the original version and secondly it's just IE and what about others?