setTitle

<h1>Please press the following buttons</h1>
<a href="javascript:void(0)" class="btn title">Configure title only</a>
<a href="javascript:void(0)" class="btn subTitle">Configure title and subtitle</a>
<a href="javascript:void(0)" class="btn clear">Clear title</a>

<script>
function ready(callback) {
  // Invoke directly if JSBridge is already injected
  if (window.AlipayJSBridge) {
    callback && callback();
  } else {
    // Otherwise listen to `AlipayJSBridgeReady` event
    document.addEventListener('AlipayJSBridgeReady', callback, false);
  }
}
ready(function(){
  document.querySelector('.title').addEventListener('click', function() {
    AlipayJSBridge.call('setTitle', {
      title: 'Title',
    });
  });

  document.querySelector('.subTitle').addEventListener('click', function() {
    AlipayJSBridge.call('setTitle', {
      title: 'Title',
      subtitle: 'Subtitle',
    });
  });

  document.querySelector('.clear').addEventListener('click', function() {
    AlipayJSBridge.call('setTitle', {
      title: ' ',
      subtitle: ' ',
    });
  });
});
</script>