Polymer 2.0 using Shady DOM document.getElementByID()

Question

I am using the Shady DOM in Polymer 2.0 by using the following script

<script>window.ShadyDOM = {force:true};</script>

I have created three custom element logon-email, logon-password and logon-button. When the paper-button is clicked I would like to get the values of the paper-inputs of logon-email and login-password. Using Polymer 1.0 I have used document.getElementById('#emailLogon').value to get the value from another custom element but this returns null in Polymer 2.0 using Shady DOM.

If what I am doing is now not possible what is the alternative to retrieving values from external custom elements from another custom element.

<link rel="import" href="../bower_components/polymer/polymer-element.html">
<link rel="import" href="shared-styles.html">

    <link rel="import" href="../bower_components/paper-input/paper-input.html">

    <dom-module id="logon-email">
      <template> 
        <style include="shared-styles">
        :host {
            display: block;

            padding: 10px;

          }

          paper-input {
            --paper-input-container-input-color: white; 
            --paper-input-container-label: { color: white; font-size: 12px};
          }

          .email_label {
            font-family: 'Roboto', 'Noto', sans-serif;
            font-size:      12px;  
            color: white;           
          }

        </style>
        <div class="email_label">Email</div>
        <paper-input label="Please enter your email address" no-label-float></paper-input>

      </template> 

      <script>
        class LogonEmail extends Polymer.Element {
          static get is() { return 'logon-email'; }
        }
        window.customElements.define(LogonEmail.is, LogonEmail);
      </script>
    </dom-module>

<dom-module id="logon-password">
  <template>
    <style include="shared-styles">
      :host {
        display: block;

        padding: 10px;

      }

      paper-input {
        --paper-input-container-input-color: white;
        --paper-input-container-label: { color: white; font-size: 12px; };    
      }    

      .password_label {
        font-family: 'Roboto', 'Noto', sans-serif;
        font-size:      12px;  
        color: white;           
      }   

    </style>

    <div class="password_label">Password</div>
    <paper-input id="logonPassword" label="Please enter your password" type="password" no-label-float></paper-input>

  </template>

  <script>
    class LogonPassword extends Polymer.Element {
      static get is() { return 'logon-password'; }
    }

    window.customElements.define(LogonPassword.is, LogonPassword);
  </script>
</dom-module>

<link rel="import" href="../bower_components/polymer/polymer-element.html">
<link rel="import" href="shared-styles.html">

<link rel="import" href="../bower_components/paper-button/paper-button.html">
<link rel="import" href="../bower_components/paper-styles/color.html">

<dom-module id="logon-button">
  <template>
    <style include="shared-styles">
      :host {
        display: block;

        padding: 10px;
      }


      paper-button {
        font-family: 'Roboto', 'Noto', sans-serif;
        font-weight: normal;
        font-size: 14px;
        -webkit-font-smoothing: antialiased;
      }  

      paper-button.green {
        background-color: var(--paper-green-500);
        color: white;
        margin: auto;
        width: 100%;
      }

    </style>

    <paper-button on-click="handleLoginClick" raised class="green">Login</paper-button    

  </template>

  <script>
    class LogonButton extends Polymer.Element {
      static get is() { return 'logon-button'; }
            connectedCallback() {
              super.connectedCallback();
            }

        handleLoginClick(){
          console.log('Login button clicked');
          var loginEmail = document.getElementById('#logonEmail');

          console.log('logonEmail ' + loginEmail);
        }
    }

    window.customElements.define(LogonButton.is, LogonButton);
  </script>
</dom-module>

Answer 1

This is the most easy approach at polymer to pass value between elements. So just define the property and set it notify:true to reflect at other elements as fallow :

<paper-input label="Please enter your email address" no-label-float value="{{emailVal}}"></paper-input>

At main document pass emailVal property to your custom elements so you have property in all 3 element like this.emailVal

 <logon-email email-val="{{emailVal}}"></logon-email>
 <logon-password email-val="{{emailVal}}"></logon-password>
 <logon-button email-val="{{emailVal}}"></logon-button>

And define this property in logon-email element and set it notify : true to reflect all property in any changes. at logon-email

  static get properties() { return { 
     emailVal:{
        type:String,
        notify:true
   },...

and at logon-button element:

 handleLoginClick(){
      console.log('Login button clicked');
      console.log('logonEmail ', this.emailVal);
    }

Hope clear .