document.querySelectorAll(".auto-adjust-sample-textarea").forEach((targetArea) => { // 初期値によってtextarea高さをadjust let lineHeight = Number(targetArea.rows); while (targetArea.scrollHeight > targetArea.offsetHeight){ lineHeight++; targetArea.rows = lineHeight; } // 入力値によってtextarea高さをadjust this.addEventListener('input', (e) => { e.srcElement.style.height = 0 e.srcElement.style.height = e.srcElement.sc
![テキストエリアを入力値によって動的に変化させる](https://cdn-ak-scissors.b.st-hatena.com/image/square/2c29b9838bec65cb5d97364606f7ce9aa15e5dc5/height=288;version=1;width=512/https%3A%2F%2Ftechblog.gmo-ap.jp%2Fwp-content%2Fuploads%2F2022%2F12%2Fa8b600666f6534a155655ef57923f561.jpg)