在javascript中模拟tab键功能

document.addEventListener('keydown', function(event) {
  if (event.key === 'Tab' && !event.shiftKey) {
    event.preventDefault();
    // 在这里添加模拟Tab键功能的代码
  }
});

document.addEventListener('keydown', function(event) {
  if (event.key === 'Tab' && !event.shiftKey) {
    event.preventDefault();
    var focusableElements = document.querySelectorAll('input, button, select, textarea, a[href], area[href], [tabindex]:not([tabindex="-1"])');
    var focusedIndex = Array.prototype.indexOf.call(focusableElements, document.activeElement);
    if (focusedIndex >= 0 && focusedIndex< focusableElements.length - 1) {
      focusableElements[focusedIndex + 1].focus();
    } else {
      focusableElements[0].focus();
    }
  }
});