jQueryでrequiredの切り替え
.removeProp('required') でプロパティの削除。.attr('required', true) でプロパティの追加。https://javascript.programmer-reference.com/jquery-removeprop/https://www.code-adviser.com/detail_19166685
.removeProp('required') でプロパティの削除。.attr('required', true) でプロパティの追加。https://javascript.programmer-reference.com/jquery-removeprop/https://www.code-adviser.com/detail_19166685
https://macoblog.com/wordpress_not_jquery/https://briarpatch.co.jp/wp-jqueryhttps://sbfl.net/blog/2019/02/01/javascript-error-messages/#Uncaught_TypeError_is_not_a_function
https://webkcampus.com/201904/1598/
https://uxmilk.jp/8796