隐藏、显示、添加或删除功能区中的按钮？

<button id="myButton">按钮</button>

<style>
#myButton {
  display: none;
}
</style>

<button id="myButton">按钮</button>

<style>
#myButton {
  display: block;
}
</style>

<div id="buttonContainer"></div>

<script>
// 添加按钮
var addButton = document.createElement("button");
addButton.innerHTML = "添加按钮";
addButton.onclick = function() {
  var newButton = document.createElement("button");
  newButton.innerHTML = "新按钮";
  document.getElementById("buttonContainer").appendChild(newButton);
};

document.getElementById("buttonContainer").appendChild(addButton);

// 删除按钮
var removeButton = document.createElement("button");
removeButton.innerHTML = "删除按钮";
removeButton.onclick = function() {
  var buttons = document.getElementById("buttonContainer").getElementsByTagName("button");
  if (buttons.length > 0) {
    buttons[buttons.length - 1].remove();
  }
};

document.getElementById("buttonContainer").appendChild(removeButton);
</script>