表单事件的Typescript接口声明

interface FormEvent {
  target: HTMLFormElement;
  preventDefault(): void;
  stopPropagation(): void;
}

interface ChangeEvent extends FormEvent {
  target: HTMLInputElement | HTMLTextAreaElement | HTMLSelectElement;
}

interface SubmitEvent extends FormEvent {}

interface InputEvent extends FormEvent {
  target: HTMLInputElement | HTMLTextAreaElement | HTMLSelectElement;
}

function handleInputChange(event: ChangeEvent) {
  const value = event.target.value;
  // 处理输入框内容改变事件
}

function handleSubmit(event: SubmitEvent) {
  event.preventDefault();
  // 处理表单提交事件
}

function handleInput(event: InputEvent) {
  const value = event.target.value;
  // 处理输入事件
}