The reopened page will reopen in the condition it was at the moment it was closed - including containing any text the user had typed into text boxes thereon - such as those on a Wikipedia edit page.
ðə ɹɪˈoʊpənd pˈeɪdʒ wɪl ɹɪˈoʊpən ɪnðə kəndˈɪʃən ɪt wʌz æt ðə mˈoʊmənt ɪt wʌz klˈoʊzd ɪŋklˈuːdɪŋ kəntˈeɪnɪŋ ˌɛni tˈɛkst ðə jˈuːzɚ hæd tˈaɪpd ˌɪntʊ tˈɛkst bˈɑːksᵻz ðɛɹˈɑːn sˈʌtʃ ɐz ðoʊz ˌɔn ɐ wˌɪkipˈiːdiə ˈɛdɪt pˈeɪdʒ.