问题描述： 在Angular中使用响应式表单验证器时，发现在浏览器的返回按钮上不起作用。

解决方法： 此问题通常是由于缺少表单状态的管理导致的。可以通过以下步骤解决该问题：

1. 在组件的构造函数中导入Angular的FormBuilder和Location服务，并创建一个表单控件：

import { Component } from '@angular/core';
import { FormBuilder, FormGroup, Validators } from '@angular/forms';
import { Location } from '@angular/common';

@Component({
  selector: 'app-your-component',
  templateUrl: './your-component.component.html',
  styleUrls: ['./your-component.component.css']
})
export class YourComponent {
  form: FormGroup;

  constructor(private fb: FormBuilder, private location: Location) {
    this.form = this.fb.group({
      // 定义你的表单控件
    });
  }

  // ...
}

2. 在组件的ngOnInit()方法中订阅表单状态的变化，并在状态变化时更新表单的状态：

import { Component, OnInit } from '@angular/core';
import { FormBuilder, FormGroup, Validators } from '@angular/forms';
import { Location } from '@angular/common';

@Component({
  selector: 'app-your-component',
  templateUrl: './your-component.component.html',
  styleUrls: ['./your-component.component.css']
})
export class YourComponent implements OnInit {
  form: FormGroup;

  constructor(private fb: FormBuilder, private location: Location) {
    this.form = this.fb.group({
      // 定义你的表单控件
    });
  }

  ngOnInit() {
    this.form.valueChanges.subscribe(() => {
      this.location.replaceState(this.location.path(), JSON.stringify(this.form.value));
    });
  }

  // ...
}

3. 在组件的ngOnDestroy()方法中取消订阅表单状态的变化：

import { Component, OnInit, OnDestroy } from '@angular/core';
import { FormBuilder, FormGroup, Validators } from '@angular/forms';
import { Location } from '@angular/common';

@Component({
  selector: 'app-your-component',
  templateUrl: './your-component.component.html',
  styleUrls: ['./your-component.component.css']
})
export class YourComponent implements OnInit, OnDestroy {
  form: FormGroup;
  private formChangesSubscription;

  constructor(private fb: FormBuilder, private location: Location) {
    this.form = this.fb.group({
      // 定义你的表单控件
    });
  }

  ngOnInit() {
    this.formChangesSubscription = this.form.valueChanges.subscribe(() => {
      this.location.replaceState(this.location.path(), JSON.stringify(this.form.value));
    });
  }

  ngOnDestroy() {
    this.formChangesSubscription.unsubscribe();
  }

  // ...
}

通过以上步骤，表单状态的变化将会被正确地记录在浏览器的历史记录中，使得返回按钮可以正常地恢复表单的状态。