13. The person reading the Megillah must have in mind that all those
listening will fulfill their obligation by listening to his reading.
Similarly, the listener must have the intention of fulfilling his
obligation when listening. He must hear each and every word. If he misses
even a single word, he does not fulfill his obligation. Therefore, the
reader should be careful that when noise and disturbances are being made
after reading Haman's name, he should be silent [and not read further]
until the noise has ceased entirely. Even so, it is proper that each
individual has a kosher Megillah scroll in front of him [during the
reading], so that he can read the text [along with the reader] word for
word by himself in a hushed tone, lest he not hear a single word being read
by the reader (1). Similarly, every woman present in the women's section,
who understands [the Megillah], is encouraged, if possible, to have a
kosher Megillah scroll in front of her to read from. [Indeed, the women
have greater reason for concern], because it is harder to hear [in the
women's section], and the women have the same level of obligation to hear
the Megillah as the men.
(If "Kiddush Le'vanah," ("Sanctification of the New Moon") has not yet been
recited that month, and the [new moon] becomes visible [for the first time
that month] on the night of the reading of the Megillah, see the end of
Chapter 97 [for instructions]).
If one doesn't have a valid handwritten Megillah, one should at least
have a printed Megillah to read from (Mishna Berura 690:19).