Safari and Safari for the iPhone support all HTML elements, including deprecated elements and even some proprietary elements that were never part of any W3C specifications. In addtion, Safari is supporting some HTML5 elements, even though the HTML5 specifications have not been finalized. I've also added the attributes that each element supports. I didn't include id, class, style, dir & title, since all elements basically support those, but I did include element specific attributes as well as some webkit only attributes.
IE8 CSS Support and Rendering Mode, IE8 debugging, etc including IE8 and CSS, IE8 compliance mode / preventing IE7 rendering in the IE8 browser, IE8 bugs, Differences between IE7 compatibility mode and IE8, IE8 CSS Hack, and IE8 Developer Toolbar (or Firebug for IE8)