Let's start with the home.html file, where most of the validation code is located. If you look at the structure of this page, it's very typical. You have <ion-navbar> with <ion-title>. The <form> element must be inside the <ion-content> area.
It's a requirement to use the <form> element for Angular validation to work. Otherwise, there will be no submit event and you cannot catch errors for each input.
form has the following attributes:
<form #f="ngForm" novalidate (ngSubmit)="onSubmit(f)">
To assign a local variable on the fly, you use the # sign. This means that you want the f variable to refer to ngForm, which is automatically created by Angular. This is a special object that contains everything related to the current form. ...
