Ist there a way to make animations for retina displays, specific iPad3 and 4?
Even with Pictures in higher resolutions the animation looks kind of blury on the retina.
Regular CSS styled elements (such as the box/rounded box/text) will be rendered in high resolution automatically by mobile safari on retina displays. For images, you can either use a high resolution image and scale it down, or use some third party JS that finds all the images on your page and replaces them with high resolution images if needed.