JavaScript uses the \ (backslash) as an escape characters for:

\' single quote

\" double quote

\ backslash

\n new line

\r carriage return

\t tab

\b backspace

\f form feed

\v vertical tab (IE < 9 treats '\v' as 'v' instead of a vertical tab ('\x0B'). If cross-browser compatibility is a concern, use \x0B instead of \v.)

\0 null character (U+0000 NULL) (only if the next character is not a decimal digit; else it’s an octal escape sequence)