/mdn2/en-US/docs/Web/JavaScript/Reference/Regular_expressionsRegular_expressions
Backreference Capturing_group Character_class Character_class_escape Character_escape Disjunction Input_boundary_assertion Literal_character Lookahead_assertion Lookbehind_assertion Modifier Named_backreference Named_capturing_group Non-capturing_group Quantifier Unicode_character_class_escape Wildcard Word_boundary_assertion