Is using fieldset and labels in XHTML discouraged?

I he开发者_StackOverflow中文版ard there was fundamental lack of web-browser comprehension of those, and often IE6,7, opera would flounder trying to display them.

Is that indeed true? Should those be avoided? And while we're at it, do they have a specific advantage when using forms? (except for the impeccably square frame around)

That sounds unreasonable. In fact, XHTML 1.x STRICT requires a block-level element like fieldset to enclose input elements. As for labels, they are valuable for users with screen readers. I would not substitute either tag.