如何在keyup事件上获取删除的字符

document.addEventListener('keyup', function(event) {
  // 在这里处理keyup事件
});

document.addEventListener('keyup', function(event) {
  if (event.key === "Backspace") {
    // 执行删除字符的操作
  }
});

document.addEventListener('keyup', function(event) {
  if (event.key === "Backspace") {
    var input = document.getElementById("input"); // 替换为实际的输入元素
    var deletedChar = input.value.substring(input.selectionStart - 1, input.selectionStart);
    console.log("Deleted character: " + deletedChar);
  }
});