このエラーメッセージに関する原因と対処に関して説明します。
エラーメッセージ(英語):
offsetleft not working
対処
関連リンク
offsetLeft - MDN - Mozilladeveloper.mozilla.org > ... > HTMLElement
https://developer.mozilla.org/ja/docs/Web/API/HTMLElement/offsetLeft
CSS transition not working for right most div on offsetLeft ...stackoverflow.com/.../css-transition-not-working-for-rig...
https://stackoverflow.com/questions/45476120/css-transition-not-working-for-right-most-div-on-offset・・・
JavaScript - element .offsetLeft & .offsetTop ...
https://stackoverflow.com/questions/16276825/javascript-element-offsetleft-offsettop-sporadic-values・・・