<ion-content padding>
  <img src="assets/imgs/logo.png" class="logo">
  <div class="spacer"></div>
  <ion-item>
    <ion-label floating>Email</ion-label>
    <ion-input (keyup)="focusFunction()" [(ngModel)]="user.email" type="email"></ion-input>
  </ion-item>
<ion-item>
    <ion-label floating>Password</ion-label>
    <ion-input (keyup)="focusFunction()" [(ngModel)]="user.password" type="email"></ion-input>
  </ion-item>

  <button full ion-button class="whiteButton" (tap)="login(user)" [disabled]="!user.email || !user.password">Login</button>
  <button full ion-button class="secondaryButton" (tap)="register()">Registrati</button>
</ion-content>

import { Component } from "@angular/core";
import { IonicPage, NavController, NavParams, ToastController, AlertController } from "ionic-angular";
import { User } from "../../classes/user/user.class";

@IonicPage()
@Component({
  selector: "page-login",
  templateUrl: "login.html"
})
export class LoginPage {
  user = {
    email: "",
    password: ""
  } as User;


focusFunction(){
    if (this.user.email.length > 0) {
      this.user.email = this.user.email.toLowerCase();
    }
    if (this.user.password.length > 0) {
      this.user.password = this.user.password.toLowerCase();
    }
  }