You must be reading this via Graphics Planet. Go to my blog site to see the demos. Graphics Planet strips out the styling needed to make the demos work.
David White created a nice SVG background he calls “The digital river” with animated circles. Unfortunately it only works in Firefox due to incorrect handling of events inside the <use> tag (which allows cloning of objects, in this case a circle) by other browsers. The other browsers apply mouse events to the referenced object rather than just the cloned objects. David’s SVG uses SMIL for animation. Unfortunately, Microsoft has declared in no uncertain terms that it will not implement SMIL in their browers. They see CSS Transitions and CSS Animations as the proper way forward for supporting animation in SVG however no browser at the moment supports this although all the browsers do support experimental (read: prefixed) CSS transitions and animations on HTML elements. Here are two experiments inspired by David’s work. The first uses CSS with CSS Transitions, the second SVG with SMIL. Pass your cursor over the circles. The CSS version uses rounded corners on <div>s to simulate circles. It has the advantage of cross-browser support (except Firefox messes up the first row of circles). The SVG version only works properly in Firefox. It is more powerful as you can easily scale circles or use other shapes. CSS Ripples