In the following case of JavaScript we fail to offer the manual fallback for saving.

<input type="text" name="admin_psw" id="admin_psw" placeholder="Enter your admin password to confirm">
<input type="submit">

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<script>$(function(){
    $('#admin_psw').on('input', function(){
        this.type = this.value.length ? 'password' : 'text';
    });
});</script>

https://jsfiddle.net/66afpv7w/

(taken from crbug.com/783755)