setBarBottomLineColor

<div style="padding-top:80px;">
  <a href="javascript:void(0)" class="btn title">设置导航栏底部细线颜色</a><br>
</div>

<script>
function ready(callback) {
  // 如果jsbridge已经注入则直接调用
  if (window.AlipayJSBridge) {
    callback && callback();
  } else {
    // 如果没有注入则监听注入的事件
    document.addEventListener('AlipayJSBridgeReady', callback, false);
  }
}
ready(function(){
  document.querySelector('.title').addEventListener('click', function() {
    AlipayJSBridge.call("setBarBottomLineColor", {
      color: parseInt('ff0000', 16)
    });
  }, false);
},false);
</script>