<div contenteditable="" class="text-div result-text-for-running-string" placeholder="Здесь будет исправленный текст"></div>
var resultTextForRunningString = document.querySelector('.result-text-for-running-string')
function inputText () {
firstInputText.dispatchEvent(new KeyboardEvent('keydown', {
key: "j",
code: "KeyJ",
which: 74,
keyCode: 74,
}))
}
inputText ()