showModalDialogのように、サブウインドウを表示して戻り値を取得する - Qiita

function openWindowToCenter(name, url, width, height) { const left = (screen.width - width) / 2; const top = (screen.height - height) / 2; const param = `width=${width}, height=${height}, left=${left}, top=${top}` return window.open(url, name, param); } function lockBody(window) { window.document.body.style.pointerEvents = 'none'; } function unlockBody(window) { window.document.body.style.pointerE