JSFiddle - React, Tailwind, and code Playground
HTML
<input type="text" id="MainContent_listSelectedDays_listDayBanks_0_moComments_0">
JavaScript
$('[id=_moComments_]').val("Found it");
<input type="text" id="MainContent_listSelectedDays_listDayBanks_0_moComments_0">
$('[id=_moComments_]').val("Found it");