title: How to add validation to fields in Odoo?
body: <p>I have to add validation in the signup form for Odoo (which is the <code>auth_signup_login_templates.xml</code> file in the auth_signup module. I need to ensure that the <code>Name</code> contains on alphabets and are within 3 to 15 characters. Right now, by default, the code for the name is:</p>
  
  <pre><code>         &lt;div class="form-group field-name"&gt;
              &lt;label for="name" class="control-label"&gt;Your Name&lt;/label&gt;
              &lt;input type="text" name="name" t-att-value="name" id="name" class="form-control" placeholder="e.g. John Doe"
                  required="required" t-att-readonly="'readonly' if only_passwords else None"
                  t-att-autofocus="'autofocus' if login and not only_passwords else None" /&gt;
          &lt;/div&gt;
  </code></pre>
  
  <p>The xml page can be found <a href="https://github.com/odoo/odoo/blob/11.0/addons/auth_signup/views/auth_signup_login_templates.xml" rel="nofollow noreferrer">here</a></p>