title: Custom attribute in B2C Signup page
body: <p>I have created custom attributes to my Azure B2C directory, and would now like to do a custom signup page but cannot figure out how to "map" the ui element to the custom attribute, please help.</p>
  
  <p>From the example my guess is I need to use "<code>extension_</code>" suffixed witht the field name in the element id? The documentation is thin in this area</p>
  
  <pre><code>&lt;div class="attrEntry"&gt;
      &lt;div class="helpText"&gt;&lt;/div&gt;
      &lt;label&gt;Loyalty number&lt;/label&gt;
      &lt;input id="extension_MemNum" class="textInput" type="text" placeholder="Loyalty number"&gt;&lt;a href="javascript:void(0)" onclick="selfAssertedClient.showHelp('Membership number');" class="tiny"&gt;What is this?&lt;/a&gt;
  &lt;/div&gt;
  </code></pre>