Comparison of Strict and Transitional XHTML:

Following transitional elements were removed from the Strict XHTML:

applet, basefont, center, dir, font, iframe, isindex, menu, noframes, s, strike, u.

Following attributes were removed from the Strict XHTML:

Attribute alink is forbidden on body.
Attribute background is forbidden on body.
Attribute bgcolor is forbidden on body, table, td, th, tr.
Attribute border is forbidden on img, object, it can be used on table.
Attribute clear is forbidden on br.
Attribute language is forbidden on script.
Attribute link is forbidden on body.
Attribute name is forbidden on form, img, it can be used on a, button, input, map, meta, object, param, select, textarea.
Attribute noshade is forbidden on hr.
Attribute nowrap is forbidden on td, th.
Attribute start is forbidden on ol.
Attribute target is forbidden on a, area, base, form, link.
Attribute text is forbidden on body.
Attribute type is forbidden on li, ol, ul, it can be used on a, button, input, link, object, param, script, style.
Attribute value is forbidden on li, it can be used on button, input, option, param.
Attribute vlink is forbidden on body.

Following elements cannot occur in the given context in the Strict XHTML:

#PCDATA cannot be a child of blockquote, body, form, noscript.
Element a cannot be a child of blockquote, body, form, noscript.
Element abbr cannot be a child of blockquote, body, form, noscript.
Element acronym cannot be a child of blockquote, body, form, noscript.
Element b cannot be a child of blockquote, body, form, noscript.
Element bdo cannot be a child of blockquote, body, form, noscript.
Element big cannot be a child of blockquote, body, form, noscript.
Element br cannot be a child of blockquote, body, form, noscript.
Element button cannot be a child of blockquote, body, form, noscript.
Element cite cannot be a child of blockquote, body, form, noscript.
Element code cannot be a child of blockquote, body, form, noscript.
Element dfn cannot be a child of blockquote, body, form, noscript.
Element em cannot be a child of blockquote, body, form, noscript.
Element i cannot be a child of blockquote, body, form, noscript.
Element img cannot be a child of blockquote, body, form, noscript.
Element input cannot be a child of blockquote, body, form, noscript.
Element kbd cannot be a child of blockquote, body, form, noscript.
Element label cannot be a child of blockquote, body, form, noscript.
Element map cannot be a child of blockquote, body, form, noscript.
Element object cannot be a child of blockquote, body, form, noscript.
Element q cannot be a child of blockquote, body, form, noscript.
Element samp cannot be a child of blockquote, body, form, noscript.
Element select cannot be a child of blockquote, body, form, noscript.
Element small cannot be a child of blockquote, body, form, noscript.
Element span cannot be a child of blockquote, body, form, noscript.
Element strong cannot be a child of blockquote, body, form, noscript.
Element sub cannot be a child of blockquote, body, form, noscript.
Element sup cannot be a child of blockquote, body, form, noscript.
Element textarea cannot be a child of blockquote, body, form, noscript.
Element tt cannot be a child of blockquote, body, form, noscript.
Element var cannot be a child of blockquote, body, form, noscript.

Element blockquote cannot contain #PCDATA, a, abbr, acronym, b, bdo, big, br, button, cite, code, dfn, em, i, img, input, kbd, label, map, object, q, samp, select, small, span, strong, sub, sup, textarea, tt, var as children.
Element body cannot contain #PCDATA, a, abbr, acronym, b, bdo, big, br, button, cite, code, dfn, em, i, img, input, kbd, label, map, object, q, samp, select, small, span, strong, sub, sup, textarea, tt, var as children.
Element form cannot contain #PCDATA, a, abbr, acronym, b, bdo, big, br, button, cite, code, dfn, em, i, img, input, kbd, label, map, object, q, samp, select, small, span, strong, sub, sup, textarea, tt, var as children.
Element noscript cannot contain #PCDATA, a, abbr, acronym, b, bdo, big, br, button, cite, code, dfn, em, i, img, input, kbd, label, map, object, q, samp, select, small, span, strong, sub, sup, textarea, tt, var as children.