| [SYMBOL] [A] [B] [C] [D] [E] [F] [G] [H] [I] [J] [K] [L] [M] [N] [O] [P] [R] [S] [T] [U] [V] [W] [X] [Y] & (ampersand) amp explosion problem predefined entities <!-- and --> (comment tags) <? and ?> (processing instruction tags) " (double quotes) ' (single quotes) |