Sweet Tooltip is a jQuery & CSS3-based tooltip, not merely a one-style tooltip but seven. This imageless tooltips are crafted using CSS power, linear-gradient, box-shadow, text-shadow, :after and :before selector, etc.
TipTip detects the edges of the browser window and will make sure the tooltip stays within the current window size. As a result the tooltip will adjust itself to be displayed above, below, to the left or to the right of the element with TipTip applied to it, depending on what is necessary to stay within the browser window. It uses zero images and is completely customizable via CSS.