jsサンプル
<!doctype html>
<html lang="ja">
<head>
<!-- Required meta tags -->
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<!-- Bootstrap CSS -->
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">
<!-- Optional JavaScript -->
<!-- jQuery first, then Popper.js, then Bootstrap JS -->
<script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js" integrity="sha384-UO2eT0CpHqdSJQ6hJty5KVphtPhzWj9WO1clHTMGa3JDZwrnQq4sF86dIHNDz0W1" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js" integrity="sha384-JjSmVgyd0p3pXB1rRibZUAYoIIy6OrQ6VrjIEaFf/nJGzIxFDsf4x0xIM+B07jRM" crossorigin="anonymous"></script>
<title>Hello, world!</title>
</head>
<body>
<h1>スタートページ</h1>
<form action="./paramsend.html" method="get">
<input type="text" id="test_param" name="test_param">
<input id="tel_btn" type="radio" name="method" value="tel">電話
<input id="mail_btn" type="radio" name="method" value="mail">メール
<input type="text" id="tel_num" name="tel_num" disabled>
<input type="submit" value="送信する">
</form>
<script>
var telBtn = document.getElementById('tel_btn');
var mailBtn = document.getElementById('mail_btn');
var telform = document.getElementById('tel_num');
window.onpopstate = function(event) {
console.log('戻ってきた');
const ev = document.createEvent('Event');
ev.initEvent('change', true, true);
document.querySelector('#tel_btn').dispatchEvent(ev);
});
/*
window.addEventListener('pageshow', function(event) {
console.log('ページ表示した');
const ev = document.createEvent('Event');
ev.initEvent('change', true, true);
document.querySelector('#tel_btn').dispatchEvent(ev);
});
*/
telBtn.addEventListener('change', function() {
console.log('telクリックされました！');
telform.disabled=false;
}, false);
mailBtn.addEventListener('change', function() {
console.log('mailクリックされました！');
telform.disabled=true;
}, false);
</script>
</body>
</html>
