title: could i form validation to a prompt alert
body: <p>is there any possibility to validate a form inside prompt alert, similar to a form validation in a page. We use ngModel for validation in a page but i dont know how to validate a form inside a prompt  </p>
  
  <pre><code>alert(){
          console.log("hi");
          let prompt = this.alertCtrl.create({
              title: 'Login',
              inputs: [
                  {
                      name: 'username',
                      placeholder: 'User Name'
                  },
                  {
                      name: 'phone',
                      placeholder: 'Phone Number'
                  }
  
              ],
  
              buttons: [
                  {
                      text: 'Cancel',
                      handler: data =&gt; {
                          console.log('Cancel clicked');
                      }
                  },
  
                  {
                      text: 'Save',
                      handler: data =&gt; {
                          console.log('Saved clicked',data);
                          this.User_data = data;
                      }
                  }
              ]
          });
          prompt.present();
      }
  </code></pre>
  
  <p>setting min and max value to input field and stating it as 'required', user name should not have numbers, phone number count should be '9'.</p>