Ionic validation

Ionic Framework ionic-v3
#1

I’m unable to validate my inputs since im new to the ionic framework, so let me know how to give validationsPreformatted text

Healthcheck
Consultatin For Dental/Eye Diagnostic Contact

*Input Required

Email 
    <ion-item>
        <ion-label>Choose your city</ion-label>
        <ion-select id="city name">
          <ion-option value="Ban">Bangalore</ion-option>
          <ion-option value="hyd">Hyderabad</ion-option>
          <ion-option value="che">Chennai</ion-option>
          <ion-option value="vij">Vijayawada</ion-option>
        </ion-select>
      </ion-item>
      <ion-item>
          <ion-label id="loc">Location</ion-label>
          <ion-select>
            <ion-option value="kp" for="loc">Kphb</ion-option>
            <ion-option value="ameer">Ameerpet</ion-option>
          </ion-select>
        </ion-item>

        <ion-item>
            <ion-label>Clinic/Hospital</ion-label>
            <ion-select>
              <ion-option value="cli">Clinic</ion-option>
              <ion-option value="Hosp">Hospital</ion-option>
            </ion-select>
          </ion-item>

       <ion-item>
           <ion-label floating>Appointment On<ion-icon ios="ios-calendar" md="md-calendar" class="dicon"></ion-icon></ion-label>
           <ion-datetime name="txtDOB" displayFormat="MM/DD/YYYY"></ion-datetime>
       </ion-item>
           
       <ion-item>
          <ion-label floating>Preffered time</ion-label>
          <ion-datetime displayFormat="h:mm a"></ion-datetime>
        </ion-item>

        <ion-item>
            <ion-label>Package</ion-label>
            <ion-select>
              <ion-option value="ey">Eye</ion-option>
              <ion-option value="den">Dental</ion-option>
            </ion-select>
          </ion-item>
          <ion-item>
              <ion-label position="floating" floating>Investigation</ion-label>
              <ion-textarea></ion-textarea>
          </ion-item>

          <button type="submit" ngSubmit ion-button (click)="NavigateToHealthviewPage()">
              Submit
          </button>
#2

Hello,

Check out this best tutorial of ionic form validation.

#3

but i have not used form there…

#4

try this <ion-input required></ion-input> might be work

OR

add if else condition ex. if input value is zero then show toast message or something like that