Assertion:
The use of block structures in MARQUEEs (such as BLOCKQUOTE) will be ignored in IE versions 3.0x and below, while in IE 4.0 and above it makes the marquee appear as a multi-line field.

Basic MARQUEE element, no width. Span nested inside:
filler text Marquee innerSpan Marquee filler text

Basic MARQUEE element, no width. Blockquote nested inside:
filler text Marquee
Blockquote
Marquee
filler text