手动取消当前视图键盘焦点，参考iOS原生功能实现

/*

• 手动取消当前视图键盘焦点，参考iOS原生功能实现
  */
  function removeBodyFocus() {
  var focusElement = document.getElementsByTagName("body")[0];
  if(focusElement.classList.contains("mui-focusin")) {
  focusElement.classList.remove("mui-focusin");
  focusElement.parentNode.replaceChild(focusElement, document.getElementsByTagName("body")[0]);
  }
  }