one small shadow is normally no problem, but often you need different shadows like box-shadow: 0px 0px 5px 10px #333, 0px 5px 10px 5px #336, 0px 0px 5px inset;. multiple shadows can create in nearly all browsers big performance problems. letters are not written in their dedicated textareas or input fields as well as the mouse might freeze etc.but there is a possibility to use a lot of shadows for one element. you can use a canvas element. on this site a canvas element works in the background (take a look into the source code) and uses a different count for every browser. it helps to solve another problem too, I will explain more about that later. in opera browser over 200 shadows are active and no problems appear at all. if an animation starts it runs with the best possible performance.all browsers have different shadow and some rendering issues (take a look at the screen shots).firefox has a nice shadows but you see its color areas if the shadow is too big. S