I used to do performance testing on websites mostly with JMeter scripts.
However, more and more projects are build with frontend MVC\'s, such as AngularJS and a curr
You can try https://github.com/kidk/felt it is build for this specific purpose.
It uses PhantomJS/SlimerJS to generate load to a website, so you get all the API/JS/CSS and image calls you would get like in a normal browser. It is still a young project, but it might be the solution you are looking for.
(This is my personal project)